(* Title: HOL/ex/PiSets.thy
ID: $Id$
Author: Florian Kammueller, University of Cambridge
Pi sets and their application.
*)
(*** Bijection between Pi in terms of => and Pi in terms of Sigma ***)
Goal "f: Pi A B ==> PiBij A B f <= Sigma A B";
by (auto_tac (claset(),
simpset() addsimps [PiBij_def,Pi_def,restrict_apply1]));
qed "PiBij_subset_Sigma";
Goal "f: Pi A B ==> (! x: A. (?! y. (x, y): (PiBij A B f)))";
by (auto_tac (claset(),
simpset() addsimps [PiBij_def,restrict_apply1]));
qed "PiBij_unique";
Goal "f: Pi A B ==> PiBij A B f : Graph A B";
by (asm_simp_tac (simpset() addsimps [Graph_def,PiBij_unique,
PiBij_subset_Sigma]) 1);
qed "PiBij_in_Graph";
Goalw [PiBij_def, Graph_def] "PiBij A B: Pi A B -> Graph A B";
by (rtac restrictI 1);
by (auto_tac (claset(), simpset() addsimps [Pi_def]));
qed "PiBij_func";
Goal "inj_on (PiBij A B) (Pi A B)";
by (rtac inj_onI 1);
by (rtac Pi_extensionality 1);
by (assume_tac 1);
by (assume_tac 1);
by (rotate_tac 1 1);
by (asm_full_simp_tac (simpset() addsimps [PiBij_def,restrict_apply1]) 1);
by (blast_tac (claset() addEs [equalityE]) 1);
qed "inj_PiBij";
Goal "PiBij A B `` (Pi A B) = Graph A B";
by (rtac equalityI 1);
by (force_tac (claset(), simpset() addsimps [image_def,PiBij_in_Graph]) 1);
by (rtac subsetI 1);
by (asm_full_simp_tac (simpset() addsimps [image_def]) 1);
by (res_inst_tac [("x","lam a: A. @ y. (a, y): x")] bexI 1);
by (rtac restrictI 2);
by (res_inst_tac [("P", "%xa. (a, xa) : x")] ex1E 2);
by (force_tac (claset(), simpset() addsimps [Graph_def]) 2);
by (full_simp_tac (simpset() addsimps [Graph_def]) 2);
by (stac select_equality 2);
by (assume_tac 2);
by (Blast_tac 2);
by (Blast_tac 2);
(* x = PiBij A B (lam a:A. @ y. (a, y) : x) *)
by (full_simp_tac (simpset() addsimps [PiBij_def,Graph_def]) 1);
by (stac restrict_apply1 1);
by (rtac restrictI 1);
by (blast_tac (claset() addSDs [[select_eq_Ex, ex1_implies_ex] MRS iffD2]) 1);
(** LEVEL 17 **)
by (rtac equalityI 1);
by (rtac subsetI 1);
by (split_all_tac 1);
by (subgoal_tac "a: A" 1);
by (Blast_tac 2);
by (asm_full_simp_tac (simpset() addsimps [restrict_apply1]) 1);
(*Blast_tac: PROOF FAILED for depth 5*)
by (fast_tac (claset() addSIs [select1_equality RS sym]) 1);
(* {(xa,y). xa : A & y = (lam a:A. @ y. (a, y) : x) xa} <= x *)
by (Clarify_tac 1);
by (asm_full_simp_tac (simpset() addsimps [restrict_apply1]) 1);
by (fast_tac (claset() addIs [selectI2]) 1);
qed "surj_PiBij";
Goal "f: Pi A B ==> \
\ (lam y: Graph A B. (Inv (Pi A B)(PiBij A B)) y)(PiBij A B f) = f";
by (asm_simp_tac
(simpset() addsimps [Inv_f_f, PiBij_func, inj_PiBij, surj_PiBij]) 1);
qed "PiBij_bij1";
Goal "[| f: Graph A B |] ==> \
\ (PiBij A B) ((lam y: (Graph A B). (Inv (Pi A B)(PiBij A B)) y) f) = f";
by (rtac (PiBij_func RS f_Inv_f) 1);
by (asm_full_simp_tac (simpset() addsimps [surj_PiBij]) 1);
by (assume_tac 1);
qed "PiBij_bij2";
Goal "Pi {} B = {f. !x. f x = (@ y. True)}";
by (asm_full_simp_tac (simpset() addsimps [Pi_def]) 1);
qed "empty_Pi";
Goal "(% x. (@ y. True)) : Pi {} B";
by (simp_tac (simpset() addsimps [empty_Pi]) 1);
qed "empty_Pi_func";
val [major] = Goalw [Pi_def] "(!!x. x: A ==> B x <= C x) ==> Pi A B <= Pi A C";
by (auto_tac (claset(),
simpset() addsimps [impOfSubs major]));
qed "Pi_mono";