let S be non empty non void ManySortedSign ; for A being non-empty MSAlgebra of S
for F being ManySortedFunction of A,(Trivial_Algebra S)
for o being OperSymbol of S
for x being Element of Args o,A holds
( (F . (the_result_sort_of o)) . ((Den o,A) . x) = 0 & (Den o,(Trivial_Algebra S)) . (F # x) = 0 )
let A be non-empty MSAlgebra of S; for F being ManySortedFunction of A,(Trivial_Algebra S)
for o being OperSymbol of S
for x being Element of Args o,A holds
( (F . (the_result_sort_of o)) . ((Den o,A) . x) = 0 & (Den o,(Trivial_Algebra S)) . (F # x) = 0 )
let F be ManySortedFunction of A,(Trivial_Algebra S); for o being OperSymbol of S
for x being Element of Args o,A holds
( (F . (the_result_sort_of o)) . ((Den o,A) . x) = 0 & (Den o,(Trivial_Algebra S)) . (F # x) = 0 )
let o be OperSymbol of S; for x being Element of Args o,A holds
( (F . (the_result_sort_of o)) . ((Den o,A) . x) = 0 & (Den o,(Trivial_Algebra S)) . (F # x) = 0 )
let x be Element of Args o,A; ( (F . (the_result_sort_of o)) . ((Den o,A) . x) = 0 & (Den o,(Trivial_Algebra S)) . (F # x) = 0 )
set I = the carrier of S;
set SA = the Sorts of A;
set T = Trivial_Algebra S;
set ST = the Sorts of (Trivial_Algebra S);
set r = the_result_sort_of o;
consider i being set such that
A1:
i in the carrier of S
and
A2:
Result o,(Trivial_Algebra S) = the Sorts of (Trivial_Algebra S) . i
by PBOOLE:150;
reconsider d = (Den o,A) . x as Element of the Sorts of A . (the_result_sort_of o) by FUNCT_2:21;
consider XX being ManySortedSet of the carrier of S such that
A3:
{XX} = the carrier of S --> {0 }
by Th6;
A4:
the Sorts of (Trivial_Algebra S) = {XX}
by A3, MSAFREE2:def 12;
then A5:
the Sorts of (Trivial_Algebra S) . (the_result_sort_of o) = {0 }
by A3, FUNCOP_1:13;
thus (F . (the_result_sort_of o)) . ((Den o,A) . x) =
(F . (the_result_sort_of o)) . d
.=
0
by A5, TARSKI:def 1
; (Den o,(Trivial_Algebra S)) . (F # x) = 0
the Sorts of (Trivial_Algebra S) . i = {0 }
by A3, A4, A1, FUNCOP_1:13;
hence
(Den o,(Trivial_Algebra S)) . (F # x) = 0
by A2, TARSKI:def 1; verum