let F, G be Element of Funcs [:NAT ,(Funcs bound_QC-variables ,bound_QC-variables ):],CQC-WFF ; ( ( for k being Element of NAT
for h being Element of Funcs bound_QC-variables ,bound_QC-variables
for p being Element of CQC-WFF st p = f . (k + 1),(h +* (x .--> (x. k))) holds
F . k,h = All (x. k),p ) & ( for k being Element of NAT
for h being Element of Funcs bound_QC-variables ,bound_QC-variables
for p being Element of CQC-WFF st p = f . (k + 1),(h +* (x .--> (x. k))) holds
G . k,h = All (x. k),p ) implies F = G )
assume A3:
for k being Element of NAT
for h being Element of Funcs bound_QC-variables ,bound_QC-variables
for p being Element of CQC-WFF st p = f . (k + 1),(h +* (x .--> (x. k))) holds
F . k,h = All (x. k),p
; ( ex k being Element of NAT ex h being Element of Funcs bound_QC-variables ,bound_QC-variables ex p being Element of CQC-WFF st
( p = f . (k + 1),(h +* (x .--> (x. k))) & not G . k,h = All (x. k),p ) or F = G )
assume A4:
for k being Element of NAT
for h being Element of Funcs bound_QC-variables ,bound_QC-variables
for p being Element of CQC-WFF st p = f . (k + 1),(h +* (x .--> (x. k))) holds
G . k,h = All (x. k),p
; F = G
for a being Element of [:NAT ,(Funcs bound_QC-variables ,bound_QC-variables ):] holds F . a = G . a
proof
let a be
Element of
[:NAT ,(Funcs bound_QC-variables ,bound_QC-variables ):];
F . a = G . a
consider k being
Element of
NAT ,
h being
Element of
Funcs bound_QC-variables ,
bound_QC-variables such that A5:
a = [k,h]
by DOMAIN_1:9;
reconsider h2 =
h +* (x .--> (x. k)) as
Function of
bound_QC-variables ,
bound_QC-variables by Lm1;
reconsider h2 =
h2 as
Element of
Funcs bound_QC-variables ,
bound_QC-variables by FUNCT_2:11;
reconsider p =
f . (k + 1),
h2 as
Element of
CQC-WFF ;
F . k,
h =
All (x. k),
p
by A3
.=
G . k,
h
by A4
;
hence
F . a = G . a
by A5;
verum
end;
hence
F = G
by FUNCT_2:113; verum