Theory HOL_Algebra_Alignment_Galois

✐‹creator "Kevin Kappelmann"›
subsection ‹Alignment With Galois Definitions from HOL-Algebra›
theory HOL_Algebra_Alignment_Galois
  imports
    "HOL-Algebra.Galois_Connection"
    HOL_Algebra_Alignment_Orders
    Galois
begin

named_theorems HOL_Algebra_galois_alignment

context galois_connection
begin

context
  fixes L R l r
  defines "L ≡ (⊑⇘𝒳⇙)↾⇘carrier 𝒳⇙↿⇘carrier 𝒳⇙" and "R ≡ (⊑⇘𝒴⇙)↾⇘carrier 𝒴⇙↿⇘carrier 𝒴⇙"
    and "l ≡ π⇧*" and "r ≡ π⇩*"
  notes defs[simp] = L_def R_def l_def r_def and rel_restrict_right_eq[simp]
    and rel_restrict_leftI[intro!] rel_restrict_leftE[elim!]
begin

interpretation galois L R l r .

lemma mono_wrt_rel_lower [HOL_Algebra_galois_alignment]: "(L ⇒ R) l"
  using lower_closed upper_closed by (fastforce intro: use_iso2[OF lower_iso])

lemma mono_wrt_rel_upper [HOL_Algebra_galois_alignment]: "(R ⇒ L) r"
  using lower_closed upper_closed by (fastforce intro: use_iso2[OF upper_iso])

lemma half_galois_prop_left [HOL_Algebra_galois_alignment]: "(L ⇩h⊴ R) l r"
  using galois_property lower_closed by (intro half_galois_prop_leftI) fastforce

lemma half_galois_prop_right [HOL_Algebra_galois_alignment]: "(L ⊴⇩h R) l r"
  using galois_property upper_closed by (intro half_galois_prop_rightI) fastforce

lemma galois_prop [HOL_Algebra_galois_alignment]: "(L ⊴ R) l r"
  using half_galois_prop_left half_galois_prop_right by blast

lemma galois_connection [HOL_Algebra_galois_alignment]: "(L ⊣ R) l r"
  using mono_wrt_rel_lower mono_wrt_rel_upper galois_prop by blast

end
end

context galois_bijection
begin

context
  fixes L R l r
  defines "L ≡ (⊑⇘𝒳⇙)↾⇘carrier 𝒳⇙↿⇘carrier 𝒳⇙" and "R ≡ (⊑⇘𝒴⇙)↾⇘carrier 𝒴⇙↿⇘carrier 𝒴⇙"
    and "l ≡ π⇧*" and "r ≡ π⇩*"
  notes defs[simp] = L_def R_def l_def r_def and rel_restrict_right_eq[simp]
    and rel_restrict_leftI[intro!] rel_restrict_leftE[elim!] in_codomE[elim!]
begin

interpretation galois R L r l .

lemma half_galois_prop_left_right_left [HOL_Algebra_galois_alignment]: "(R ⇩h⊴ L) r l"
  using gal_bij_conn.right lower_inv_eq upper_closed upper_inv_eq
  by (intro half_galois_prop_leftI; elim left_GaloisE) (auto; metis)

lemma half_galois_prop_right_right_left [HOL_Algebra_galois_alignment]: "(R ⊴⇩h L) r l"
  using gal_bij_conn.left lower_closed lower_inv_eq upper_inv_eq
  by (intro half_galois_prop_rightI; elim Galois_rightE) (auto; metis)

lemma prop_right_right_left [HOL_Algebra_galois_alignment]: "(R ⊴ L) r l"
  using half_galois_prop_left_right_left half_galois_prop_right_right_left by blast

lemma galois_equivalence [HOL_Algebra_galois_alignment]: "(L ≡⇩G R) l r"
  using gal_bij_conn.galois_connection prop_right_right_left
  by (intro galois.galois_equivalenceI) auto

end
end


end