let S be non empty non void ManySortedSign ; for o being OperSymbol of S
for U1, U2 being non-empty MSAlgebra of S
for F being ManySortedFunction of U1,U2
for x being Element of Args o,U1
for n being set st n in dom (the_arity_of o) holds
(F # x) . n = (F . ((the_arity_of o) /. n)) . (x . n)
let o be OperSymbol of S; for U1, U2 being non-empty MSAlgebra of S
for F being ManySortedFunction of U1,U2
for x being Element of Args o,U1
for n being set st n in dom (the_arity_of o) holds
(F # x) . n = (F . ((the_arity_of o) /. n)) . (x . n)
let U1, U2 be non-empty MSAlgebra of S; for F being ManySortedFunction of U1,U2
for x being Element of Args o,U1
for n being set st n in dom (the_arity_of o) holds
(F # x) . n = (F . ((the_arity_of o) /. n)) . (x . n)
let F be ManySortedFunction of U1,U2; for x being Element of Args o,U1
for n being set st n in dom (the_arity_of o) holds
(F # x) . n = (F . ((the_arity_of o) /. n)) . (x . n)
let x be Element of Args o,U1; for n being set st n in dom (the_arity_of o) holds
(F # x) . n = (F . ((the_arity_of o) /. n)) . (x . n)
let n be set ; ( n in dom (the_arity_of o) implies (F # x) . n = (F . ((the_arity_of o) /. n)) . (x . n) )
assume A1:
n in dom (the_arity_of o)
; (F # x) . n = (F . ((the_arity_of o) /. n)) . (x . n)
dom F = the carrier of S
by PARTFUN1:def 4;
then
rng (the_arity_of o) c= dom F
;
then A2:
n in dom (F * (the_arity_of o))
by A1, RELAT_1:46;
A3:
x in product (doms (F * (the_arity_of o)))
by Th13;
thus (F # x) . n =
((Frege (F * (the_arity_of o))) . x) . n
by MSUALG_3:def 7
.=
((F * (the_arity_of o)) .. x) . n
by A3, PRALG_2:def 8
.=
((F * (the_arity_of o)) . n) . (x . n)
by A2, PRALG_1:def 17
.=
(F . ((the_arity_of o) . n)) . (x . n)
by A2, FUNCT_1:22
.=
(F . ((the_arity_of o) /. n)) . (x . n)
by A1, PARTFUN1:def 8
; verum