Theory Set_Comprehension_Pointfree_Examples

theory Set_Comprehension_Pointfree_Examples
imports Main
(*  Title:      HOL/ex/Set_Comprehension_Pointfree_Examples.thy
    Author:     Lukas Bulwahn, Rafal Kolanski
    Copyright   2012 TU Muenchen
*)

section ‹Examples for the set comprehension to pointfree simproc›

theory Set_Comprehension_Pointfree_Examples
imports Main
begin

declare [[simproc add: finite_Collect]]

lemma
  "finite (UNIV::'a set) ==> finite {p. EX x::'a. p = (x, x)}"
  by simp

lemma
  "finite A ==> finite B ==> finite {f a b| a b. a : A ∧ b : B}"
  by simp
  
lemma
  "finite B ==> finite A' ==> finite {f a b| a b. a : A ∧ a : A' ∧ b : B}"
  by simp

lemma
  "finite A ==> finite B ==> finite {f a b| a b. a : A ∧ b : B ∧ b : B'}"
  by simp

lemma
  "finite A ==> finite B ==> finite C ==> finite {f a b c| a b c. a : A ∧ b : B ∧ c : C}"
  by simp

lemma
  "finite A ==> finite B ==> finite C ==> finite D ==>
     finite {f a b c d| a b c d. a : A ∧ b : B ∧ c : C ∧ d : D}"
  by simp

lemma
  "finite A ==> finite B ==> finite C ==> finite D ==> finite E ==>
    finite {f a b c d e | a b c d e. a : A ∧ b : B ∧ c : C ∧ d : D ∧ e : E}"
  by simp

lemma
  "finite A ==> finite B ==> finite C ==> finite D ==> finite E ⟹
    finite {f a d c b e | e b c d a. b : B ∧ a : A ∧ e : E' ∧ c : C ∧ d : D ∧ e : E ∧ b : B'}"
  by simp

lemma
  "⟦ finite A ; finite B ; finite C ; finite D ⟧
  ⟹ finite ({f a b c d| a b c d. a : A ∧ b : B ∧ c : C ∧ d : D})"
  by simp

lemma
  "finite ((λ(a,b,c,d). f a b c d) ` (A × B × C × D))
  ⟹ finite ({f a b c d| a b c d. a : A ∧ b : B ∧ c : C ∧ d : D})"
  by simp

lemma
  "finite S ==> finite {s'. EX s:S. s' = f a e s}"
  by simp

lemma
  "finite A ==> finite B ==> finite {f a b| a b. a : A ∧ b : B ∧ a ∉ Z}"
  by simp

lemma
  "finite A ==> finite B ==> finite R ==> finite {f a b x y| a b x y. a : A ∧ b : B ∧ (x,y) ∈ R}"
by simp

lemma
  "finite A ==> finite B ==> finite R ==> finite {f a b x y| a b x y. a : A ∧ (x,y) ∈ R ∧ b : B}"
by simp

lemma
  "finite A ==> finite B ==> finite R ==> finite {f a (x, b) y| y b x a. a : A ∧ (x,y) ∈ R ∧ b : B}"
by simp

lemma
  "finite A ==> finite AA ==> finite B ==> finite {f a b| a b. (a : A ∨ a : AA) ∧ b : B ∧ a ∉ Z}"
by simp

lemma
  "finite A1 ==> finite A2 ==> finite A3 ==> finite A4 ==> finite A5 ==> finite B ==>
     finite {f a b c | a b c. ((a : A1 ∧ a : A2) ∨ (a : A3 ∧ (a : A4 ∨ a : A5))) ∧ b : B ∧ a ∉ Z}"
apply simp
oops

lemma "finite B ==> finite {c. EX x. x : B & c = a * x}"
by simp

lemma
  "finite A ==> finite B ==> finite {f a * g b |a b. a : A & b : B}"
by simp

lemma
  "finite S ==> inj (%(x, y). g x y) ==> finite {f x y| x y. g x y : S}"
  by (auto intro: finite_vimageI)

lemma
  "finite A ==> finite S ==> inj (%(x, y). g x y) ==> finite {f x y z | x y z. g x y : S & z : A}"
  by (auto intro: finite_vimageI)

lemma
  "finite S ==> finite A ==> inj (%(x, y). g x y) ==> inj (%(x, y). h x y)
    ==> finite {f a b c d | a b c d. g a c : S & h b d : A}"
  by (auto intro: finite_vimageI)

lemma
  assumes "finite S" shows "finite {(a,b,c,d). ([a, b], [c, d]) : S}"
using assms by (auto intro!: finite_vimageI simp add: inj_on_def)
  (* injectivity to be automated with further rules and automation *)

schematic_goal (* check interaction with schematics *)
  "finite {x :: ?'A ⇒ ?'B ⇒ bool. ∃a b. x = Pair_Rep a b}
   = finite ((λ(b :: ?'B, a:: ?'A). Pair_Rep a b) ` (UNIV × UNIV))"
  by simp

declare [[simproc del: finite_Collect]]


section ‹Testing simproc in code generation›

definition union :: "nat set => nat set => nat set"
where
  "union A B = {x. x : A ∨ x : B}"

definition common_subsets :: "nat set => nat set => nat set set"
where
  "common_subsets S1 S2 = {S. S ⊆ S1 ∧ S ⊆ S2}"

definition products :: "nat set => nat set => nat set"
where
  "products A B = {c. EX a b. a : A & b : B & c = a * b}"

export_code products in Haskell

export_code union common_subsets products in Haskell

end