Theory FO_Ordered_Resolution_Prover_Revisited

(*  Title:       Application of the Saturation Framework to Bachmair and Ganzinger's RP
    Author:      Sophie Tourret <stourret at mpi-inf.mpg.de>, 2018-2020
    Author:      Jasmin Blanchette <j.c.blanchette at vu.nl>, 2020
*)

section ‹Application of the Saturation Framework to Bachmair and Ganzinger's \textsf{RP}›

theory FO_Ordered_Resolution_Prover_Revisited
  imports
    Ordered_Resolution_Prover.FO_Ordered_Resolution_Prover
    Saturation_Framework.Given_Clause_Architectures
    Clausal_Calculus
    Soundness
begin

text ‹The main results about Bachmair and Ganzinger's \textsf{RP} prover, as established in
Section 4.3 of their \emph{Handbook} chapter and formalized by Schlichtkrull et al., are re-proved
here using the saturation framework of Waldmann et al.›


subsection ‹Setup›

no_notation true_lit (infix ⊨l 50)
no_notation true_cls (infix  50)
no_notation true_clss (infix ⊨s 50)
no_notation true_cls_mset (infix ⊨m 50)

hide_type (open) Inference_System.inference

hide_const (open) Inference_System.Infer Inference_System.main_prem_of
  Inference_System.side_prems_of Inference_System.prems_of Inference_System.concl_of
  Inference_System.concls_of Inference_System.infer_from

type_synonym 'a old_inference = "'a Inference_System.inference"

abbreviation "old_Infer  Inference_System.Infer"
abbreviation "old_side_prems_of  Inference_System.side_prems_of"
abbreviation "old_main_prem_of  Inference_System.main_prem_of"
abbreviation "old_concl_of  Inference_System.concl_of"
abbreviation "old_prems_of  Inference_System.prems_of"
abbreviation "old_concls_of  Inference_System.concls_of"
abbreviation "old_infer_from  Inference_System.infer_from"

lemmas old_infer_from_def = Inference_System.infer_from_def


subsection ‹Library›

lemma set_zip_replicate_right[simp]:
  "set (zip xs (replicate (length xs) y)) = (λx. (x, y)) ` set xs"
  by (induct xs) auto


subsection ‹Ground Layer›

context FO_resolution_prover
begin

no_notation RP (infix  50)
notation RP (infix ↝RP 50)

interpretation gr: ground_resolution_with_selection "S_M S M"
  using selection_axioms by unfold_locales (fact S_M_selects_subseteq S_M_selects_neg_lits)+

definition G_Inf :: "'a clause set  'a clause inference set" where
  "G_Inf M = {Infer (CAs @ [DA]) E |CAs DA AAs As E. gr.ord_resolve M CAs DA AAs As E}"

lemma G_Inf_have_prems: "ι  G_Inf M  prems_of ι  []"
  unfolding G_Inf_def by auto

lemma G_Inf_reductive: "ι  G_Inf M  concl_of ι < main_prem_of ι"
  unfolding G_Inf_def by (auto dest: gr.ord_resolve_reductive)

interpretation G: sound_inference_system "G_Inf M" "{{#}}" "(⊫e)"
proof
  fix ι
  assume i_in: "ι  G_Inf M"
  moreover
  {
    fix I
    assume I_ent_prems: "I ⊫s set (prems_of ι)"
    obtain CAs AAs As where
      the_inf: "gr.ord_resolve M CAs (main_prem_of ι) AAs As (concl_of ι)" and
      CAs: "CAs = side_prems_of ι"
      using i_in unfolding G_Inf_def by auto
    then have "I  concl_of ι"
      using gr.ord_resolve_sound[of M CAs "main_prem_of ι" AAs As "concl_of ι" I]
      by (metis I_ent_prems G_Inf_have_prems i_in insert_is_Un set_mset_mset set_prems_of
          true_clss_insert true_clss_set_mset)
  }
  ultimately show "set (inference.prems_of ι) ⊫e {concl_of ι}"
    by simp
qed

interpretation G: clausal_counterex_reducing_inference_system "G_Inf M" "gr.INTERP M"
proof
  fix N D
  assume
    "{#}  N" and
    "D  N" and
    "¬ gr.INTERP M N  D" and
    "C. C  N  ¬ gr.INTERP M N  C  D  C"
  then obtain CAs AAs As E where
    cas_in: "set CAs  N" and
    n_mod_cas: "gr.INTERP M N ⊫m mset CAs" and
    ca_prod: "CA. CA  set CAs  gr.production M N CA  {}" and
    e_res: "gr.ord_resolve M CAs D AAs As E" and
    n_nmod_e: "¬ gr.INTERP M N  E" and
    e_lt_d: "E < D"
    using gr.ord_resolve_counterex_reducing by blast
  define ι where
    "ι = Infer (CAs @ [D]) E"

  have "ι  G_Inf M"
    unfolding ι_def G_Inf_def using e_res by auto
  moreover have "prems_of ι  []"
    unfolding ι_def by simp
  moreover have "main_prem_of ι = D"
    unfolding ι_def by simp
  moreover have "set (side_prems_of ι)  N"
    unfolding ι_def using cas_in by simp
  moreover have "gr.INTERP M N ⊫s set (side_prems_of ι)"
    unfolding ι_def using n_mod_cas ca_prod by (simp add: gr.productive_imp_INTERP true_clss_def)
  moreover have "¬ gr.INTERP M N  concl_of ι"
    unfolding ι_def using n_nmod_e by simp
  moreover have "concl_of ι < D"
    unfolding ι_def using e_lt_d by simp
  ultimately show "ι  G_Inf M. prems_of ι  []  main_prem_of ι = D  set (side_prems_of ι)  N 
    gr.INTERP M N ⊫s set (side_prems_of ι)  ¬ gr.INTERP M N  concl_of ι  concl_of ι < D"
    by blast
qed

interpretation G: clausal_counterex_reducing_calculus_with_standard_redundancy "G_Inf M"
  "gr.INTERP M"
  using G_Inf_have_prems G_Inf_reductive
  by (unfold_locales) simp_all

interpretation G: statically_complete_calculus "{{#}}" "G_Inf M" "(⊫e)" "G.Red_I M" G.Red_F
  by unfold_locales (use G.clausal_saturated_complete in blast)


subsection ‹First-Order Layer›

abbreviation 𝒢_F :: 'a clause  'a clause set where
  𝒢_F  grounding_of_cls

abbreviation 𝒢_Fset :: 'a clause set  'a clause set where
  𝒢_Fset  grounding_of_clss

lemmas 𝒢_F_def = grounding_of_cls_def
lemmas 𝒢_Fset_def = grounding_of_clss_def

definition 𝒢_I :: 'a clause set  'a clause inference  'a clause inference set where
  𝒢_I M ι = {Infer (prems_of ι ⋅⋅cl ρs) (concl_of ι  ρ) |ρ ρs.
     is_ground_subst_list ρs  is_ground_subst ρ
      Infer (prems_of ι ⋅⋅cl ρs) (concl_of ι  ρ)  G_Inf M}

abbreviation
  𝒢_I_opt :: 'a clause set  'a clause inference  'a clause inference set option
where
  𝒢_I_opt M ι  Some (𝒢_I M ι)

definition F_Inf :: "'a clause inference set" where
  "F_Inf = {Infer (CAs @ [DA]) E | CAs DA AAs As σ E. ord_resolve_rename S CAs DA AAs As σ E}"

lemma F_Inf_have_prems: "ι  F_Inf  prems_of ι  []"
  unfolding F_Inf_def by force

interpretation F: lifting_intersection F_Inf "{{#}}" UNIV G_Inf "λN. (⊫e)" G.Red_I "λN. G.Red_F"
  "{{#}}" "λN. 𝒢_F" 𝒢_I_opt "λD C C'. False"
proof (unfold_locales; (intro ballI)?)
  show "UNIV  {}"
    by (rule UNIV_not_empty)
next
  show "consequence_relation {{#}} (⊫e)"
    by (fact consequence_relation_axioms)
next
  show "M. tiebreaker_lifting {{#}} F_Inf {{#}} (⊫e) (G_Inf M) (G.Red_I M) G.Red_F 𝒢_F (𝒢_I_opt M)
    (λD C C'. False)"
  proof
    fix M ι
    show "the (𝒢_I_opt M ι)  G.Red_I M (𝒢_F (concl_of ι))"
      unfolding option.sel
    proof
      fix ι'
      assume "ι'  𝒢_I M ι"
      then obtain ρ ρs where
        ι': "ι' = Infer (prems_of ι ⋅⋅cl ρs) (concl_of ι  ρ)" and
        ρ_gr: "is_ground_subst ρ" and
        ρ_infer: "Infer (prems_of ι ⋅⋅cl ρs) (concl_of ι  ρ)  G_Inf M"
        unfolding 𝒢_I_def by blast

      show "ι'  G.Red_I M (𝒢_F (concl_of ι))"
        unfolding G.Red_I_def G.redundant_infer_def mem_Collect_eq using ι' ρ_gr ρ_infer
        by (metis inference.sel(2) G_Inf_reductive empty_iff ground_subst_ground_cls
            grounding_of_cls_ground insert_iff subst_cls_eq_grounding_of_cls_subset_eq
            true_clss_union)
    qed
  qed (auto simp: 𝒢_F_def ex_ground_subst)
qed

notation F.entails_𝒢 (infix ⊫𝒢e 50)

lemma F_entails_𝒢_iff: "N1 ⊫𝒢e N2   (𝒢_F ` N1) ⊫e  (𝒢_F ` N2)"
  unfolding F.entails_𝒢_def by simp

lemma true_Union_grounding_of_cls_iff:
  "I ⊫s (C  N. {C  σ |σ. is_ground_subst σ})  (σ. is_ground_subst σ  I ⊫s N ⋅cs σ)"
  unfolding true_clss_def subst_clss_def by blast

interpretation F: sound_inference_system F_Inf "{{#}}" "(⊫𝒢e)"
proof
  fix ι
  assume i_in: "ι  F_Inf"
  moreover
  {
    fix I η
    assume
      I_entails_prems: "σ. is_ground_subst σ  I ⊫s set (prems_of ι) ⋅cs σ" and
      η_gr: "is_ground_subst η"
    obtain CAs AAs As σ where
      the_inf: "ord_resolve_rename S CAs (main_prem_of ι) AAs As σ (concl_of ι)" and
      CAs: "CAs = side_prems_of ι"
      using i_in unfolding F_Inf_def by auto
    have prems: "mset (prems_of ι) = mset (side_prems_of ι) + {#main_prem_of ι#}"
      by (metis (no_types) F_Inf_have_prems[OF i_in] add.right_neutral append_Cons append_Nil2
          append_butlast_last_id mset.simps(2) mset_rev mset_single_iff_right rev_append
          rev_is_Nil_conv union_mset_add_mset_right)
    have "I  concl_of ι  η"
      using ord_resolve_rename_sound[OF the_inf, of I η, OF _ η_gr]
      unfolding CAs prems[symmetric] using I_entails_prems
      by (metis set_mset_mset set_mset_subst_cls_mset_subst_clss true_clss_set_mset)
  }
  ultimately show "set (inference.prems_of ι) ⊫𝒢e {concl_of ι}"
    unfolding F.entails_𝒢_def 𝒢_F_def true_Union_grounding_of_cls_iff by auto
qed

lemma G_Inf_overapprox_F_Inf: "ι0  G.Inf_from M ( (𝒢_F ` M))  ι  F.Inf_from M. ι0  𝒢_I M ι"
proof -
  assume ι0_in: "ι0  G.Inf_from M ( (𝒢_F ` M))"
  have prems_ι0_in: "set (prems_of ι0)   (𝒢_F ` M)"
    using ι0_in unfolding G.Inf_from_def by simp
  note ι0_G_Inf = G.Inf_if_Inf_from[OF ι0_in]
  then obtain CAs DA AAs As E where
    gr_res: gr.ord_resolve M CAs DA AAs As E and
    ι0_is: ι0 = Infer (CAs @ [DA]) E
    unfolding G_Inf_def by auto

  have CAs_in: set CAs  set (prems_of ι0)
    by (simp add: ι0_is subsetI)
  then have ground_CAs: is_ground_cls_list CAs
    using prems_ι0_in union_grounding_of_cls_ground is_ground_cls_list_def is_ground_clss_def by auto
  have DA_in: DA  set (prems_of ι0)
    using ι0_is by simp
  then have ground_DA: is_ground_cls DA
    using prems_ι0_in union_grounding_of_cls_ground is_ground_clss_def by auto
  obtain σ where
    grounded_res: ord_resolve (S_M S M) CAs DA AAs As σ E
    using ground_ord_resolve_imp_ord_resolve[OF ground_DA ground_CAs
        gr.ground_resolution_with_selection_axioms gr_res] by auto
  have prems_ground: {DA}  set CAs  𝒢_Fset M
    using prems_ι0_in CAs_in DA_in unfolding 𝒢_Fset_def by fast

  obtain ηs η η2 CAs0 DA0 AAs0 As0 E0 τ where
    ground_n: "is_ground_subst η" and
    ground_ns: "is_ground_subst_list ηs" and
    ground_n2: "is_ground_subst η2" and
    ngr_res: "ord_resolve_rename S CAs0 DA0 AAs0 As0 τ E0" and
    CAs0_is: "CAs0 ⋅⋅cl ηs = CAs" and
    DA0_is: "DA0  η = DA" and
    E0_is: "E0  η2 = E"  and
    prems_in: "{DA0}  set CAs0  M" and
    len_CAs0: "length CAs0 = length CAs" and
    len_ns: "length ηs = length CAs"
    using ord_resolve_rename_lifting[OF _ grounded_res selection_axioms prems_ground] sel_stable
    by smt

  have "length CAs0 = length ηs"
    using len_CAs0 len_ns by simp
  then have ι0_is': "ι0 = Infer ((CAs0 @ [DA0]) ⋅⋅cl (ηs @ [η])) (E0  η2)"
    unfolding ι0_is by (auto simp: CAs0_is[symmetric] DA0_is[symmetric] E0_is[symmetric])

  define ι :: "'a clause inference" where
    "ι = Infer (CAs0 @ [DA0]) E0"

  have i_F_Inf: ι  F_Inf
    unfolding ι_def F_Inf_def using ngr_res by auto
  have "ρ ρs. ι0 = Infer ((CAs0 @ [DA0]) ⋅⋅cl ρs) (E0  ρ)  is_ground_subst_list ρs
     is_ground_subst ρ  Infer ((CAs0 @ [DA0]) ⋅⋅cl ρs) (E0  ρ)  G_Inf M"
    by (rule exI[of _ η2], rule exI[of _ "ηs @ [η]"], use ground_ns in
        auto intro: ground_n ground_n2 ι0_G_Inf[unfolded ι0_is']
           simp: ι0_is' is_ground_subst_list_def)
  then have ι0  𝒢_I M ι
    unfolding 𝒢_I_def ι_def CAs0_is[symmetric] DA0_is[symmetric] E0_is[symmetric] by simp
  moreover have ι  F.Inf_from M
    using prems_in i_F_Inf unfolding F.Inf_from_def ι_def by simp
  ultimately show ?thesis
    by blast
qed

interpretation F: statically_complete_calculus "{{#}}" F_Inf "(⊫𝒢e)" F.Red_I_𝒢 F.Red_F_𝒢_empty
proof (rule F.stat_ref_comp_to_non_ground_fam_inter; clarsimp; (intro exI)?)
  show "M. statically_complete_calculus {{#}} (G_Inf M) (⊫e) (G.Red_I M) G.Red_F"
    by (fact G.statically_complete_calculus_axioms)
next
  fix N
  assume "F.saturated N"
  show "F.ground.Inf_from_q N ( (𝒢_F ` N))  {ι. ι'  F.Inf_from N. ι  𝒢_I N ι'}
     G.Red_I N ( (𝒢_F ` N))"
    using G_Inf_overapprox_F_Inf unfolding F.ground.Inf_from_q_def 𝒢_I_def by fastforce
qed


subsection ‹Labeled First-Order or Given Clause Layer›

datatype label = New | Processed | Old

abbreviation F_Equiv :: "'a clause  'a clause  bool" (infix  50) where
  "C  D  generalizes C D  generalizes D C"

abbreviation F_Prec :: "'a clause  'a clause  bool" (infix ≺⋅ 50) where
  "C ≺⋅ D  strictly_generalizes C D"

fun L_Prec :: "label  label  bool" (infix ⊏l 50) where
  "Old ⊏l l  l  Old"
| "Processed ⊏l l  l = New"
| "New ⊏l l  False"

lemma irrefl_L_Prec: "¬ l ⊏l l"
  by (cases l) auto

lemma trans_L_Prec: "l1 ⊏l l2  l2 ⊏l l3  l1 ⊏l l3"
  by (cases l1; cases l2; cases l3) auto

lemma wf_L_Prec: "wfP (⊏l)"
  by (metis L_Prec.elims(2) L_Prec.simps(3) not_accp_down wfp_iff_accp)

interpretation FL: given_clause "{{#}}" F_Inf "{{#}}" UNIV "λN. (⊫e)" G_Inf G.Red_I
  "λN. G.Red_F" "λN. 𝒢_F" 𝒢_I_opt "(≐)" "(≺⋅)" "(⊏l)" Old
proof (unfold_locales; (intro ballI)?)
  show "equivp (≐)"
    unfolding equivp_def by (meson generalizes_refl generalizes_trans)
next
  show "po_on (≺⋅) UNIV"
    unfolding po_on_def irreflp_on_def transp_on_def
    using strictly_generalizes_irrefl strictly_generalizes_trans by auto
next
  show "wfp_on (≺⋅) UNIV"
    unfolding wfp_on_UNIV by (metis wf_strictly_generalizes)
next
  show "po_on (⊏l) UNIV"
    unfolding po_on_def irreflp_on_def transp_on_def using irrefl_L_Prec trans_L_Prec by blast
next
  show "wfp_on (⊏l) UNIV"
    unfolding wfp_on_UNIV by (rule wf_L_Prec)
next
  fix C1 D1 C2 D2
  assume
    "C1  D1"
    "C2  D2"
    "C1 ≺⋅ C2"
  then show "D1 ≺⋅ D2"
    by (smt antisym size_mset_mono size_subst strictly_generalizes_def generalizes_def
        generalizes_trans)
next
  fix N C1 C2
  assume "C1  C2"
  then show "𝒢_F C1  𝒢_F C2"
    unfolding generalizes_def 𝒢_F_def by clarsimp (metis is_ground_comp_subst subst_cls_comp_subst)
next
  fix N C2 C1
  assume "C2 ≺⋅ C1"
  then show "𝒢_F C1  𝒢_F C2"
    unfolding strictly_generalizes_def generalizes_def 𝒢_F_def
    by clarsimp (metis is_ground_comp_subst subst_cls_comp_subst)
next
  show "l. L_Prec Old l"
    using L_Prec.simps(1) by blast
qed (auto simp: F_Inf_have_prems)

notation FL.Prec_FL (infix  50)
notation FL.entails_𝒢_L (infix ⊫𝒢Le 50)
notation FL.derive (infix ⊳L 50)
notation FL.step (infix ↝GC 50)

lemma FL_Red_F_eq:
  "FL.Red_F N =
   {C. D  𝒢_F (fst C). D  G.Red_F ( (𝒢_F ` fst ` N))  (E  N. E  C  D  𝒢_F (fst E))}"
  unfolding FL.Red_F_def FL.Red_F_𝒢_q_def by auto

lemma mem_FL_Red_F_because_G_Red_F:
  "(D  𝒢_F (fst Cl). D  G.Red_F ( (𝒢_F ` fst ` N)))  Cl  FL.Red_F N"
  unfolding FL_Red_F_eq by auto

lemma mem_FL_Red_F_because_Prec_FL:
  "(D  𝒢_F (fst Cl). El  N. El  Cl  D  𝒢_F (fst El))  Cl  FL.Red_F N"
  unfolding FL_Red_F_eq by auto


subsection ‹Resolution Prover Layer›

interpretation sq: selection "S_Q Sts"
  unfolding S_Q_def using S_M_selects_subseteq S_M_selects_neg_lits selection_axioms
  by unfold_locales auto

interpretation gd: ground_resolution_with_selection "S_Q Sts"
  by unfold_locales

interpretation src: standard_redundancy_criterion_counterex_reducing "gd.ord_Γ Sts"
  "ground_resolution_with_selection.INTERP (S_Q Sts)"
  by unfold_locales

definition lclss_of_state :: "'a state  ('a clause × label) set" where
  "lclss_of_state St =
   (λC. (C, New)) ` N_of_state St  (λC. (C, Processed)) ` P_of_state St
    (λC. (C, Old)) ` Q_of_state St"

lemma image_hd_lclss_of_state[simp]: "fst ` lclss_of_state St = clss_of_state St"
  unfolding lclss_of_state_def by (auto simp: image_Un image_comp)

lemma insert_lclss_of_state[simp]:
  "insert (C, New) (lclss_of_state (N, P, Q)) = lclss_of_state (N  {C}, P, Q)"
  "insert (C, Processed) (lclss_of_state (N, P, Q)) = lclss_of_state (N, P  {C}, Q)"
  "insert (C, Old) (lclss_of_state (N, P, Q)) = lclss_of_state (N, P, Q  {C})"
  unfolding lclss_of_state_def image_def by auto

lemma union_lclss_of_state[simp]:
  "lclss_of_state (N1, P1, Q1)  lclss_of_state (N2, P2, Q2) =
   lclss_of_state (N1  N2, P1  P2, Q1  Q2)"
  unfolding lclss_of_state_def by auto

lemma mem_lclss_of_state[simp]:
  "(C, New)  lclss_of_state (N, P, Q)  C  N"
  "(C, Processed)  lclss_of_state (N, P, Q)  C  P"
  "(C, Old)  lclss_of_state (N, P, Q)  C  Q"
  unfolding lclss_of_state_def image_def by auto

lemma lclss_Liminf_commute:
  "Liminf_llist (lmap lclss_of_state Sts) = lclss_of_state (Liminf_state Sts)"
proof -
  have Liminf_llist (lmap lclss_of_state Sts) =
    (λC. (C, New)) ` Liminf_llist (lmap N_of_state Sts) 
    (λC. (C, Processed)) ` Liminf_llist (lmap P_of_state Sts) 
    (λC. (C, Old)) ` Liminf_llist (lmap Q_of_state Sts)
    unfolding lclss_of_state_def using Liminf_llist_lmap_union Liminf_llist_lmap_image
    by (smt Pair_inject Un_iff disjoint_iff_not_equal imageE inj_onI label.simps(1,3,5)
        llist.map_cong)
 then show ?thesis
   unfolding lclss_of_state_def Liminf_state_def by auto
qed

lemma GC_tautology_step:
  assumes tauto: "Neg A ∈# C" "Pos A ∈# C"
  shows "lclss_of_state (N  {C}, P, Q) ↝GC lclss_of_state (N, P, Q)"
proof -
  have cθ_red: "  G.Red_F (D  N'. 𝒢_F (fst D))" if in_g: "  𝒢_F C"
    for N' :: "('a clause × label) set" and 
  proof -
    obtain θ where
      " = C  θ"
       using in_g unfolding 𝒢_F_def by blast
    then have "Neg (A ⋅a θ) ∈# " and "Pos (A ⋅a θ) ∈# "
      using tauto Neg_Melem_subst_atm_subst_cls Pos_Melem_subst_atm_subst_cls by auto
    then have "{} ⊫e {}"
      unfolding true_clss_def true_cls_def true_lit_def if_distrib_fun
      by (metis literal.disc literal.sel singletonD)
    then show ?thesis
      unfolding G.Red_F_def by auto
  qed

  show ?thesis
  proof (rule FL.step.process[of _ "lclss_of_state (N, P, Q)" "{(C, New)}" _ "{}"])
    show {(C, New)}  FL.Red_F_𝒢 (lclss_of_state (N, P, Q)  {})
      using mem_FL_Red_F_because_G_Red_F cθ_red[of _ "lclss_of_state (N, P, Q)"]
      unfolding lclss_of_state_def by auto
  qed (auto simp: lclss_of_state_def FL.active_subset_def)
qed

lemma GC_subsumption_step:
  assumes
    d_in: "Dl  N" and
    d_sub_c: "strictly_subsumes (fst Dl) (fst Cl)  subsumes (fst Dl) (fst Cl)  snd Dl ⊏l snd Cl"
  shows "N  {Cl} ↝GC N"
proof -
  have d_sub'_c: "Cl  FL.Red_F {Dl}  Dl  Cl"
  proof (cases "size (fst Dl) = size (fst Cl)")
    case True
      assume sizes_eq: size (fst Dl) = size (fst Cl)
      have size (fst Dl) = size (fst Cl) 
        strictly_subsumes (fst Dl) (fst Cl)  subsumes (fst Dl) (fst Cl)  snd Dl ⊏l snd Cl 
        Dl  Cl
        unfolding FL.Prec_FL_def
        unfolding generalizes_def strictly_generalizes_def strictly_subsumes_def subsumes_def
        by (metis size_subst subset_mset.order_refl subseteq_mset_size_eql)
    then have "Dl  Cl"
      using sizes_eq d_sub_c by auto
    then show ?thesis
      by (rule disjI2)
  next
    case False
    then have d_ssub_c: "strictly_subsumes (fst Dl) (fst Cl)"
      using d_sub_c unfolding strictly_subsumes_def subsumes_def
      by (metis size_subst strict_subset_subst_strictly_subsumes strictly_subsumes_antisym
          subset_mset.antisym_conv2)
    have "Cl  FL.Red_F {Dl}"
    proof (rule mem_FL_Red_F_because_G_Red_F)
      show D  𝒢_F (fst Cl). D  G.Red_F ( (𝒢_F ` fst ` {Dl}))
        using d_ssub_c unfolding G.Red_F_def strictly_subsumes_def subsumes_def 𝒢_F_def
      proof clarsimp
        fix σ σ'
        assume
          fst_not_in: σ. ¬ fst Cl  σ ⊆# fst Dl and
          fst_in: fst Dl  σ ⊆# fst Cl and
          gr_sig: is_ground_subst σ'
        have {fst Dl  σ  σ'}  {fst Dl  σ |σ. is_ground_subst σ}
          using gr_sig
          by (metis (mono_tags, lifting) is_ground_comp_subst mem_Collect_eq singletonD subsetI
              subst_cls_comp_subst)
        moreover have I. I ⊫s {fst Dl  σ  σ'}  I  fst Cl  σ'
          using fst_in
          by (meson subst_cls_mono_mset true_clss_insert true_clss_subclause)
        moreover have D  {fst Dl  σ  σ'}. D < fst Cl  σ'
          using fst_not_in fst_in gr_sig
        proof clarify
          show σ. ¬ fst Cl  σ ⊆# fst Dl  fst Dl  σ ⊆# fst Cl  is_ground_subst σ' 
            fst Dl  σ  σ' < fst Cl  σ'
            by (metis False size_subst subset_imp_less_mset subset_mset.le_less subst_subset_mono)
        qed
        ultimately show DD  {fst Dl  σ |σ. is_ground_subst σ}.
           (I. I ⊫s DD  I  fst Cl  σ')  (D  DD. D < fst Cl  σ')
          by blast
      qed
    qed
    then show ?thesis
      by (rule disjI1)
  qed
  show ?thesis
  proof (rule FL.step.process[of _ N "{Cl}" _ "{}"], simp+)
    show Cl  FL.Red_F_𝒢 N
      using d_sub'_c unfolding FL_Red_F_eq
    proof -
      have D. D  𝒢_F (fst Cl)  E  N. E  Cl  D  𝒢_F (fst E) 
        D  𝒢_F (fst Cl). D  G.Red_F (𝒢_F (fst Dl))  Dl  Cl  D  𝒢_F (fst Dl) 
        D  G.Red_F (a  N. 𝒢_F (fst a))
        by (metis (no_types, lifting) G.Red_F_of_subset SUP_upper d_in subset_iff)
      moreover have D. D  𝒢_F (fst Cl)  E  N. E  Cl  D  𝒢_F (fst E)  Dl  Cl 
        D  G.Red_F (a  N. 𝒢_F (fst a))
        by (smt FL.Prec_FL_def FL.equiv_F_grounding FL.prec_F_grounding UNIV_witness d_in in_mono)
      ultimately show Cl  {C. D  𝒢_F (fst C). D  G.Red_F ( (𝒢_F ` fst ` {Dl})) 
        (E  {Dl}. E  C  D  𝒢_F (fst E))}  Dl  Cl 
        Cl  {C. D  𝒢_F (fst C). D  G.Red_F ( (𝒢_F ` fst ` N)) 
        (E  N. E  C  D  𝒢_F (fst E))}
        by auto
    qed
  qed (simp add: FL.active_subset_def)
qed

lemma GC_reduction_step:
  assumes
    young: "snd Dl  Old" and
    d_sub_c: "fst Dl ⊂# fst Cl"
  shows "N  {Cl} ↝GC N  {Dl}"
proof (rule FL.step.process[of _ N "{Cl}" _ "{Dl}"])
  have "Cl  FL.Red_F {Dl}"
  proof (rule mem_FL_Red_F_because_G_Red_F)
    show D  𝒢_F (fst Cl). D  G.Red_F ( (𝒢_F ` fst ` {Dl}))
      using d_sub_c unfolding G.Red_F_def strictly_subsumes_def subsumes_def 𝒢_F_def
    proof clarsimp
      fix σ
      assume is_ground_subst σ
      then have {fst Dl  σ}  {fst Dl  σ |σ. is_ground_subst σ}
        by blast
      moreover have fst Dl  σ < fst Cl  σ
        using subst_subset_mono[OF d_sub_c, of σ] by (simp add: subset_imp_less_mset)
      moreover have I. I  fst Dl  σ  I  fst Cl  σ
        using subst_subset_mono[OF d_sub_c] true_clss_subclause by fast
      ultimately show DD  {fst Dl  σ |σ. is_ground_subst σ}. (I. I ⊫s DD  I  fst Cl  σ)
         (D  DD. D < fst Cl  σ)
        by blast
    qed
  qed
  then show "{Cl}  FL.Red_F (N  {Dl})"
    using FL.Red_F_of_subset by blast
qed (auto simp: FL.active_subset_def young)

lemma GC_processing_step: "N  {(C, New)} ↝GC N  {(C, Processed)}"
proof (rule FL.step.process[of _ N "{(C, New)}" _ "{(C, Processed)}"])
  have "(C, New)  FL.Red_F {(C, Processed)}"
    by (rule mem_FL_Red_F_because_Prec_FL) (simp add: FL.Prec_FL_def generalizes_refl)
  then show "{(C, New)}  FL.Red_F (N  {(C, Processed)})"
    using FL.Red_F_of_subset by blast
qed (auto simp: FL.active_subset_def)

lemma old_inferences_between_eq_new_inferences_between:
  "old_concl_of ` inference_system.inferences_between (ord_FO_Γ S) N C =
   concl_of ` F.Inf_between N {C}" (is "?rp = ?f")
proof (intro set_eqI iffI)
  fix E
  assume e_in: "E  old_concl_of ` inference_system.inferences_between (ord_FO_Γ S) N C"

  obtain CAs DA AAs As σ where
    e_res: "ord_resolve_rename S CAs DA AAs As σ E" and
    cd_sub: "set CAs  {DA}  N  {C}" and
    c_in: "C  set CAs  {DA}"
    using e_in unfolding inference_system.inferences_between_def infer_from_def ord_FO_Γ_def by auto

  show "E  concl_of ` F.Inf_between N {C}"
    unfolding F.Inf_between_alt F.Inf_from_def
  proof -
    have Infer (CAs @ [DA]) E  F_Inf  set (prems_of (Infer (CAs @ [DA]) E))  insert C N 
      C  set (prems_of (Infer (CAs @ [DA]) E))  E = concl_of (Infer (CAs @ [DA]) E)
      using e_res cd_sub c_in F_Inf_def by auto
    then show E  concl_of ` {ι  F_Inf. ι  {ι  F_Inf. set (prems_of ι)  N  {C}} 
      set (prems_of ι)  {C}  {}}
      by (smt Un_insert_right boolean_algebra_cancel.sup0 disjoint_insert mem_Collect_eq image_def)
  qed
next
  fix E
  assume e_in: "E  concl_of ` F.Inf_between N {C}"

  obtain CAs DA AAs As σ where
    e_res: "ord_resolve_rename S CAs DA AAs As σ E" and
    cd_sub: "set CAs  {DA}  N  {C}" and
    c_in: "C  set CAs  {DA}"
    using e_in unfolding F.Inf_between_alt F.Inf_from_def F_Inf_def inference_system.Inf_between_alt
      inference_system.Inf_from_def
    by (auto simp: image_def Bex_def)

  show "E  old_concl_of ` inference_system.inferences_between (ord_FO_Γ S) N C"
    unfolding inference_system.inferences_between_def infer_from_def ord_FO_Γ_def
    using e_res cd_sub c_in
    by (clarsimp simp: image_def Bex_def, rule_tac x = "old_Infer (mset CAs) DA E" in exI, auto)
qed

lemma GC_inference_step:
  assumes
    young: "l  Old" and
    no_active: "FL.active_subset M = {}" and
    m_sup: "fst ` M  old_concl_of ` inference_system.inferences_between (ord_FO_Γ S)
      (fst ` FL.active_subset N) C"
  shows "N  {(C, l)} ↝GC N  {(C, Old)}  M"
proof (rule FL.step.infer[of _ N C l _ M])
  have m_sup': "fst ` M  concl_of ` F.Inf_between (fst ` FL.active_subset N) {C}"
    using m_sup unfolding old_inferences_between_eq_new_inferences_between .

  show "F.Inf_between (fst ` FL.active_subset N) {C}  F.Red_I (fst ` (N  {(C, Old)}  M))"
  proof
    fix ι
    assume ι_in_if2: "ι  F.Inf_between (fst ` FL.active_subset N) {C}"
    note ι_in = F.Inf_if_Inf_between[OF ι_in_if2]
    have "concl_of ι  fst ` M"
      using m_sup' ι_in_if2 m_sup' by (auto simp: image_def Collect_mono_iff F.Inf_between_alt)
    then have "concl_of ι  fst ` (N  {(C, Old)}  M)"
      by auto
    then show "ι  F.Red_I_𝒢 (fst ` (N  {(C, Old)}  M))"
      by (rule F.Red_I_of_Inf_to_N[OF ι_in])
  qed
qed (use young no_active in auto)

lemma RP_step_imp_GC_step: "St ↝RP St'  lclss_of_state St ↝GC lclss_of_state St'"
proof (induction rule: RP.induct)
  case (tautology_deletion A C N P Q)
  then show ?case
    by (rule GC_tautology_step)
next
  case (forward_subsumption D P Q C N)
  note d_in = this(1) and d_sub_c = this(2)
  show ?case
  proof (cases "D  P")
    case True
    then show ?thesis
      using GC_subsumption_step[of "(D, Processed)" "lclss_of_state (N, P, Q)" "(C, New)"] d_sub_c
      by auto
  next
    case False
    then have "D  Q"
      using d_in by simp
    then show ?thesis
      using GC_subsumption_step[of "(D, Old)" "lclss_of_state (N, P, Q)" "(C, New)"] d_sub_c by auto
  qed
next
  case (backward_subsumption_P D N C P Q)
  note d_in = this(1) and d_ssub_c = this(2)
  then show ?case
    using GC_subsumption_step[of "(D, New)" "lclss_of_state (N, P, Q)" "(C, Processed)"] d_ssub_c
    by auto
next
  case (backward_subsumption_Q D N C P Q)
  note d_in = this(1) and d_ssub_c = this(2)
  then show ?case
    using GC_subsumption_step[of "(D, New)" "lclss_of_state (N, P, Q)" "(C, Old)"] d_ssub_c by auto
next
  case (forward_reduction D L' P Q L σ C N)
  show ?case
    using GC_reduction_step[of "(C, New)" "(C + {#L#}, New)" "lclss_of_state (N, P, Q)"] by auto
next
  case (backward_reduction_P D L' N L σ C P Q)
  show ?case
    using GC_reduction_step[of "(C, Processed)" "(C + {#L#}, Processed)" "lclss_of_state (N, P, Q)"]
    by auto
next
  case (backward_reduction_Q D L' N L σ C P Q)
  show ?case
    using GC_reduction_step[of "(C, Processed)" "(C + {#L#}, Old)" "lclss_of_state (N, P, Q)"]
    by auto
next
  case (clause_processing N C P Q)
  show ?case
    using GC_processing_step[of "lclss_of_state (N, P, Q)" C] by auto
next
  case (inference_computation N Q C P)
  note n = this(1)
  show ?case
  proof -
    have FL.active_subset (lclss_of_state (N, {}, {})) = {}
      unfolding n by (auto simp: FL.active_subset_def)
    moreover have old_concls_of (inference_system.inferences_between (ord_FO_Γ S)
      (fst ` FL.active_subset (lclss_of_state ({}, P, Q))) C)  N
      unfolding n inference_system.inferences_between_def image_def mem_Collect_eq
        lclss_of_state_def infer_from_def
      by (auto simp: FL.active_subset_def)
    ultimately have lclss_of_state ({}, insert C P, Q) ↝GC lclss_of_state (N, P, insert C Q)
      using GC_inference_step[of Processed "lclss_of_state (N, {}, {})"
        "lclss_of_state ({}, P, Q)" C, simplified] by blast
    then show ?case
      by (auto simp: FL.active_subset_def)
  qed
qed

lemma RP_derivation_imp_GC_derivation: "chain (↝RP) Sts  chain (↝GC) (lmap lclss_of_state Sts)"
  using chain_lmap RP_step_imp_GC_step by blast

lemma RP_step_imp_derive_step: "St ↝RP St'  lclss_of_state St ⊳L lclss_of_state St'"
  by (rule FL.one_step_equiv) (rule RP_step_imp_GC_step)

lemma RP_derivation_imp_derive_derivation:
  "chain (↝RP) Sts  chain (⊳L) (lmap lclss_of_state Sts)"
  using chain_lmap RP_step_imp_derive_step by blast

theorem RP_sound_new_statement:
  assumes
    deriv: "chain (↝RP) Sts" and
    bot_in: "{#}  clss_of_state (Liminf_state Sts)"
  shows "clss_of_state (lhd Sts) ⊫𝒢e {{#}}"
proof -
  have "clss_of_state (Liminf_state Sts) ⊫𝒢e {{#}}"
    using F.subset_entailed bot_in by auto
  then have "fst ` Liminf_llist (lmap lclss_of_state Sts) ⊫𝒢e {{#}}"
    by (metis image_hd_lclss_of_state lclss_Liminf_commute)
  then have "Liminf_llist (lmap lclss_of_state Sts) ⊫𝒢Le FL.Bot_FL"
    using FL.labeled_entailment_lifting by simp
  then have "lhd (lmap lclss_of_state Sts) ⊫𝒢Le FL.Bot_FL"
  proof -
    assume FL.entails_𝒢 (Liminf_llist (lmap lclss_of_state Sts)) ({{#}} × UNIV)
    moreover have chain (⊳L) (lmap lclss_of_state Sts)
      using deriv RP_derivation_imp_derive_derivation by simp
    moreover have chain FL.entails_𝒢 (lmap lclss_of_state Sts)
      by (smt F_entails_𝒢_iff FL.labeled_entailment_lifting RP_model chain_lmap deriv 𝒢_Fset_def
        image_hd_lclss_of_state)
    ultimately show FL.entails_𝒢 (lhd (lmap lclss_of_state Sts)) ({{#}} × UNIV)
      using FL.unsat_limit_iff by blast
  qed
  then have "lclss_of_state (lhd Sts) ⊫𝒢Le FL.Bot_FL"
    using chain_not_lnull deriv by fastforce
  then show ?thesis
    unfolding FL.entails_𝒢_L_def F.entails_𝒢_def lclss_of_state_def by auto
qed

theorem RP_saturated_if_fair_new_statement:
  assumes
    deriv: "chain (↝RP) Sts" and
    init: "FL.active_subset (lclss_of_state (lhd Sts)) = {}" and
    final: "FL.passive_subset (Liminf_llist (lmap lclss_of_state Sts)) = {}"
  shows "FL.saturated (Liminf_llist (lmap lclss_of_state Sts))"
proof -
  note nnil = chain_not_lnull[OF deriv]
  have gc_deriv: "chain (↝GC) (lmap lclss_of_state Sts)"
    by (rule RP_derivation_imp_GC_derivation[OF deriv])
  show ?thesis
    using nnil init final
      FL.fair_implies_Liminf_saturated[OF FL.gc_to_red[OF gc_deriv] FL.gc_fair[OF gc_deriv]] by simp
qed

corollary RP_complete_if_fair_new_statement:
  assumes
    deriv: "chain (↝RP) Sts" and
    init: "FL.active_subset (lclss_of_state (lhd Sts)) = {}" and
    final: "FL.passive_subset (Liminf_llist (lmap lclss_of_state Sts)) = {}" and
    unsat: "grounding_of_state (lhd Sts) ⊫e {{#}}"
  shows "{#}  Q_of_state (Liminf_state Sts)"
proof -
  note nnil = chain_not_lnull[OF deriv]
  note len = chain_length_pos[OF deriv]
  have gc_deriv: "chain (↝GC) (lmap lclss_of_state Sts)"
    by (rule RP_derivation_imp_GC_derivation[OF deriv])

  have hd_lcls: "fst ` lhd (lmap lclss_of_state Sts) = lhd (lmap clss_of_state Sts)"
    using len zero_enat_def by auto
  have hd_unsat: "fst ` lhd (lmap lclss_of_state Sts) ⊫𝒢e {{#}}"
    unfolding hd_lcls F_entails_𝒢_iff unfolding true_clss_def using unsat unfolding 𝒢_Fset_def
    by (metis (no_types, lifting) chain_length_pos gc_deriv gr.ex_min_counterex i0_less
        llength_eq_0 llength_lmap llength_lmap llist.map_sel(1) true_cls_empty true_clss_singleton)
  have "BL  {{#}} × UNIV. BL  Liminf_llist (lmap lclss_of_state Sts)"
    by (rule FL.gc_complete_Liminf[OF gc_deriv,of "{#}"])
      (use final hd_unsat in auto simp: init nnil)
  then show ?thesis
    unfolding Liminf_state_def lclss_Liminf_commute
    using final[unfolded FL.passive_subset_def] Liminf_state_def lclss_Liminf_commute by fastforce
qed


subsection ‹Alternative Derivation of Previous \textsf{RP} Results›

lemma old_fair_imp_new_fair:
  assumes
    nnul: "¬ lnull Sts" and
    fair: "fair_state_seq Sts" and
    empty_Q0: "Q_of_state (lhd Sts) = {}"
  shows
    "FL.active_subset (lclss_of_state (lhd Sts)) = {}" and
    "FL.passive_subset (Liminf_llist (lmap lclss_of_state Sts)) = {}"
proof -
  show "FL.active_subset (lclss_of_state (lhd Sts)) = {}"
    using nnul empty_Q0 unfolding FL.active_subset_def by (cases Sts) auto
next
  show "FL.passive_subset (Liminf_llist (lmap lclss_of_state Sts)) = {}"
    using fair
    unfolding fair_state_seq_def FL.passive_subset_def lclss_Liminf_commute lclss_of_state_def
    by auto
qed

lemma old_redundant_infer_iff:
  "src.redundant_infer N γ 
   (DD. DD  N  DD  set_mset (old_side_prems_of γ) ⊫e {old_concl_of γ}
       (D  DD. D < old_main_prem_of γ))"
  (is "?lhs  ?rhs")
proof
  assume ?rhs
  then obtain DD0 where
    "DD0  N" and
    "DD0  set_mset (old_side_prems_of γ) ⊫e {old_concl_of γ}" and
    "D  DD0. D < old_main_prem_of γ"
    by blast
  then obtain DD where
    fin_dd: "finite DD" and
    dd_in: "DD  N" and
    dd_un: "DD  set_mset (old_side_prems_of γ) ⊫e {old_concl_of γ}" and
    all_dd: "D  DD. D < old_main_prem_of γ"
    using entails_concl_compact_union[of "{old_concl_of γ}" DD0 "set_mset (old_side_prems_of γ)"]
    by fast
  show ?lhs
    unfolding src.redundant_infer_def using fin_dd dd_in dd_un all_dd
    by simp (metis finite_set_mset_mset_set true_clss_set_mset)
qed (auto simp: src.redundant_infer_def)

definition old_infer_of :: "'a clause inference  'a old_inference" where
  "old_infer_of ι = old_Infer (mset (side_prems_of ι)) (main_prem_of ι) (concl_of ι)"

lemma new_redundant_infer_imp_old_redundant_infer:
  "G.redundant_infer N ι  src.redundant_infer N (old_infer_of ι)"
  unfolding old_redundant_infer_iff G.redundant_infer_def old_infer_of_def by simp

lemma saturated_imp_saturated_RP:
  assumes
    satur: "FL.saturated (Liminf_llist (lmap lclss_of_state Sts))" and
    no_passive: "FL.passive_subset (Liminf_llist (lmap lclss_of_state Sts)) = {}"
  shows "src.saturated_upto Sts (grounding_of_state (Liminf_state Sts))"
proof -
  define Q where
    "Q = Liminf_llist (lmap Q_of_state Sts)"
  define Ql where
    "Ql = (λC. (C, Old)) ` Q"
  define G where
    "G =  (𝒢_F ` Q)"

  have n_empty: "N_of_state (Liminf_state Sts) = {}" and
    p_empty: "P_of_state (Liminf_state Sts) = {}"
    using no_passive[unfolded FL.passive_subset_def] Liminf_state_def lclss_Liminf_commute
    by fastforce+
  then have limuls_eq: "Liminf_llist (lmap lclss_of_state Sts) = Ql"
    unfolding Ql_def Q_def using Liminf_state_def lclss_Liminf_commute lclss_of_state_def by auto
  have clst_eq: "clss_of_state (Liminf_state Sts) = Q"
    unfolding n_empty p_empty Q_def by (auto simp: Liminf_state_def)
  have gflimuls_eq: "(Cl  Ql. 𝒢_F (fst Cl)) = G"
    unfolding Ql_def G_def by auto

  have "gd.inferences_from Sts G  src.Ri Sts G"
  proof
    fix γ
    assume γ_inf: "γ  gd.inferences_from Sts G"

    obtain ι where
      ι_inff: "ι  G.Inf_from Q G" and
      γ: "γ = old_infer_of ι"
      using γ_inf
      unfolding gd.inferences_from_def old_infer_from_def G.Inf_from_def old_infer_of_def
    proof (atomize_elim, clarify)
      assume
        g_is: γ  gd.ord_Γ Sts and
        prems_in: set_mset (old_side_prems_of γ + {#old_main_prem_of γ#})  G
      obtain CAs DA AAs As E where main_in: DA  G and side_in: set CAs  G and
        g_is2: γ = old_Infer (mset CAs) DA E and
        ord_res: gd.ord_resolve Sts CAs DA AAs As E
        using g_is prems_in unfolding gd.ord_Γ_def by auto
      define ι_γ where "ι_γ = Infer (CAs @ [DA]) E"
      then have ι_γ  G_Inf Q  using Q_of_state.simps g_is g_is2 ord_res Liminf_state_def S_Q_def
        unfolding gd.ord_Γ_def G_Inf_def Q_def by auto
      moreover have set (prems_of ι_γ)  G
        using g_is2 prems_in unfolding ι_γ_def by simp
      moreover have γ = old_Infer (mset (side_prems_of ι_γ)) (main_prem_of ι_γ) (concl_of ι_γ)
        using g_is2 unfolding ι_γ_def by simp
      ultimately show
        ι. ι  {ι  G_Inf Q. set (prems_of ι)  G}  γ = old_Infer (mset (side_prems_of ι))
         (main_prem_of ι) (concl_of ι)
        by blast
    qed
    obtain ι' where
      ι'_inff: "ι'  F.Inf_from Q" and
      ι_in_ι': "ι  𝒢_I Q ι'"
      using G_Inf_overapprox_F_Inf ι_inff unfolding G_def by blast

    note ι'_inf = F.Inf_if_Inf_from[OF ι'_inff]

    let ?olds = "replicate (length (prems_of ι')) Old"

    obtain ι'' and l0 where
      ι'': "ι'' = Infer (zip (prems_of ι') ?olds) (concl_of ι', l0)" and
      ι''_inf: "ι''  FL.Inf_FL"
      using FL.Inf_F_to_Inf_FL[OF ι'_inf, of ?olds, simplified] by simp

    have "set (prems_of ι'')  Ql"
      using ι'_inff[unfolded F.Inf_from_def, simplified] unfolding ι'' Ql_def by auto
    then have "ι''  FL.Inf_from Ql"
      unfolding FL.Inf_from_def using ι''_inf by simp
    moreover have "ι' = FL.to_F ι''"
      unfolding ι'' unfolding FL.to_F_def by simp
    ultimately have "ι  G.Red_I Q G"
      using ι_in_ι'
        FL.sat_inf_imp_ground_red_fam_inter[OF satur, unfolded limuls_eq gflimuls_eq, simplified]
      by blast
    then have "G.redundant_infer G ι"
      unfolding G.Red_I_def by auto
    then have γ_red: "src.redundant_infer G γ"
      unfolding γ by (rule new_redundant_infer_imp_old_redundant_infer)
    moreover have "γ  gd.ord_Γ Sts"
      using γ_inf gd.inferences_from_def by blast
    ultimately show "γ  src.Ri Sts G"
      unfolding src.Ri_def by auto
  qed
  then show ?thesis
    unfolding G_def clst_eq src.saturated_upto_def
    by clarsimp (smt Diff_subset gd.inferences_from_mono subset_eq 𝒢_Fset_def)
qed

theorem RP_sound_old_statement:
  assumes
    deriv: "chain (↝RP) Sts" and
    bot_in: "{#}  clss_of_state (Liminf_state Sts)"
  shows "¬ satisfiable (grounding_of_state (lhd Sts))"
  using RP_sound_new_statement[OF deriv bot_in] unfolding F_entails_𝒢_iff 𝒢_Fset_def by simp

text ‹The theorem below is stated differently than the original theorem in \textsf{RP}:
The grounding of the limit might be a strict subset of the limit of the groundings. Because
saturation is neither monotone nor antimonotone, the two results are incomparable. See also
@{thm [source] grounding_of_state_Liminf_state_subseteq}.›

theorem RP_saturated_if_fair_old_statement_altered:
  assumes
    deriv: "chain (↝RP) Sts" and
    fair: "fair_state_seq Sts" and
    empty_Q0: "Q_of_state (lhd Sts) = {}"
  shows "src.saturated_upto Sts (grounding_of_state (Liminf_state Sts))"
proof -
  note fair' = old_fair_imp_new_fair[OF chain_not_lnull[OF deriv] fair empty_Q0]
  show ?thesis
    by (rule saturated_imp_saturated_RP[OF _ fair'(2)], rule RP_saturated_if_fair_new_statement)
      (rule deriv fair')+
qed

corollary RP_complete_if_fair_old_statement:
  assumes
    deriv: "chain (↝RP) Sts" and
    fair: "fair_state_seq Sts" and
    empty_Q0: "Q_of_state (lhd Sts) = {}" and
    unsat: "¬ satisfiable (grounding_of_state (lhd Sts))"
  shows "{#}  Q_of_state (Liminf_state Sts)"
proof (rule RP_complete_if_fair_new_statement)
  show 𝒢_Fset (N_of_state (lhd Sts)  P_of_state (lhd Sts)  Q_of_state (lhd Sts)) ⊫e {{#}}
    using unsat unfolding F_entails_𝒢_iff by auto
qed (rule deriv old_fair_imp_new_fair[OF chain_not_lnull[OF deriv] fair empty_Q0])+

end

end