/usr/share/hol88-2.02.19940316/contrib/quotient/quotientfns.ml is in hol88-contrib-source 2.02.19940316-35.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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This file defines functions needed for constructing
quotient types.
%
%
AUTHOR: TON KALKER
DATE : 2 JUNE 1989
%
let check_quotient_def =
set_fail_prefix `not equivalence theorem!: `
(\thm.
let asl,w = dest_thm thm in
let t1,t2 = dest_comb w in
let name,ty = (dest_const t1 ? failwith `operator`) in
let base_type = ((hd o snd o dest_type o
hd o snd o dest_type) ty ? failwith `types`) in
if not (asl = []) then failwith `assumptions`
if not (name = `EQUIVALENCE`) then failwith `not EQUIVALENCE`
if not (is_const t2) then failwith `operand`
else t2,base_type);;
% <name>_ISO_DEF added for new define_new_type_bijections. %
% TFM 90.04.11 HOL88 Version 1.12 %
let construct_quot_ty(name,thm) =
let equi, base_type = check_quotient_def thm in
let exists_thm = MATCH_MP (DISCH_ALL EXISTS_CLASS) thm and
is_mk_class_thm = MATCH_MP (DISCH_ALL IS_MK_CLASS) thm in
let w = concl exists_thm in
let tm = (fst o dest_comb o snd o dest_exists) w in
let thm1 = new_type_definition(name,tm,exists_thm) in
let ISO =
define_new_type_bijections
(name ^ `_ISO_DEF`) (`ABS_` ^ name) (`REP_` ^ name) thm1 in
let thml =
[prove_abs_fn_one_one ISO; prove_abs_fn_onto ISO] in
let thm3 = ( GEN_ALL o
(REWRITE_RULE[is_mk_class_thm]) o
(SPEC "MK_CLASS ^equi (x':^base_type)") o
(SPEC "MK_CLASS ^equi (x:^base_type)"))(el 1 thml) in
let thm4 = (el 2 thml) in
let current = current_theory() in
let [ABS_name] = filter
(\tm.((fst o dest_const) tm) = (`ABS_` ^ name))
(constants current) in
let quot_ty = ((el 2) o snd o dest_type o type_of) ABS_name in
let PROJ_name = mk_var(`PROJ_` ^ name,":^base_type ->^quot_ty") in
let proj = new_definition(`PROJ_` ^name,
"^PROJ_name x = ^ABS_name (MK_CLASS ^equi x)") in
proj,thm3,thm4,base_type,quot_ty,equi;;
let prove_proj_onto name thm proj thm4 base_type quot_ty=
let surjective_thm = MATCH_MP (DISCH_ALL SURJECTIVE_LEMMA) thm in
let PROJ_name = mk_const(`PROJ_` ^ name,":^base_type ->^quot_ty") in
let tm = "ONTO ^PROJ_name" in
TAC_PROOF(
([],tm),
REWRITE_TAC[ONTO_DEF;proj] THEN
STRIP_TAC THEN
STRIP_ASSUME_TAC (SPEC "y:^quot_ty" thm4) THEN
ASSUM_LIST
(\asl.STRIP_ASSUME_TAC (MATCH_MP surjective_thm (hd asl))) THEN
EXISTS_TAC "x:^base_type" THEN
ASM_REWRITE_TAC[]);;
let prove_proj_universal name thm proj thm3 base_type quot_ty equi =
let universal_thm = MATCH_MP (DISCH_ALL UNIVERSAL_LEMMA) thm in
let PROJ_name = mk_const(`PROJ_` ^ name,":^base_type ->^quot_ty") in
let tm = "!x y.((^PROJ_name x = ^PROJ_name y) = (^equi x y))" in
TAC_PROOF(
([],tm),
REWRITE_TAC[proj;thm3;universal_thm]);;
let prove_proj_factor name base_type quot_ty thml =
let thm1 = INST_TYPE[(base_type,":*");(quot_ty,":***")] FACTOR_THM in
let thm2 = SPEC "f:^base_type -> **" thm1 in
let PROJ_name = mk_const(`PROJ_` ^ name,":^base_type ->^quot_ty") in
let thm3 = SPEC "^PROJ_name" thm2 in
let thm4 = GEN_ALL thm3 in
REWRITE_RULE thml thm4;;
let define_quotient_type(name,thm) =
let proj,thm3,thm4,base_type,quot_ty,equi = construct_quot_ty(name,thm)
in
let string1 = `SURJ_PROJ_` ^ name ^ `_THM` and
string2 = `UNIV_PROJ_` ^ name ^ `_THM` and
string3 = `FACTOR_PROJ_` ^ name ^ `_THM`
in
let thm1 = save_thm(string1,
prove_proj_onto name thm proj thm4 base_type quot_ty) and
thm2 = save_thm(string2,
prove_proj_universal name thm proj thm3 base_type quot_ty equi)
in
let thm3 = save_thm(string3,
prove_proj_factor name base_type quot_ty [thm1;thm2])
in [thm1;thm2;thm3];;
let FACTOR_TAC surj_thml univ_thml =
MATCH_MP_TAC FACTOR_THM THEN
REWRITE_TAC([ONTO_SURJ_THM;P;]@surj_thml) THEN
CONV_TAC (RAND_CONV (ABS_CONV PROD_CONV)) THEN
CONV_TAC PROD_CONV THEN
BETA_TAC THEN
REWRITE_TAC([PAIR_EQ]@univ_thml);;
let new_unique_specification =
set_fail_prefix `new_unique_specification`
(\name [flag,c] thm.
(
let thm1 = (BETA_RULE o (CONV_RULE EXISTS_UNIQUE_CONV)) thm
in
let ex_thm,uniq_thm = CONJ_PAIR thm1
in
let thm2 = (new_specification name [flag,c] ex_thm ?
(print_string (name ^ ` already defined`);
print_newline();
definition (current_theory()) name))
in
let [newconst] =
filter
(\d.(c = (fst o dest_const) d))
(constants (current_theory()))
in
let thm3 = SPEC newconst uniq_thm
in
let thm4 = REWRITE_RULE[thm2] thm3
in
let x = fst(dest_forall(concl thm4))
in
let thm5 = CONV_RULE (GEN_ALPHA_CONV "f:^(type_of x)") thm4
in
let thm6 = (save_thm((name ^ `_UNIQUE`), thm5) ?
(print_string (name ^ `_UNIQUE already present`);
print_newline();
theorem (current_theory()) (name ^ `_UNIQUE`)))
in
[thm2;thm6]
));;
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