let I be non empty set ; for S being non empty non void ManySortedSign
for A being MSAlgebra-Family of I,S
for o being OperSymbol of S
for x being Element of Args o,(product A)
for n being set st n in dom (the_arity_of o) holds
x . n in product (Carrier A,((the_arity_of o) /. n))
let S be non empty non void ManySortedSign ; for A being MSAlgebra-Family of I,S
for o being OperSymbol of S
for x being Element of Args o,(product A)
for n being set st n in dom (the_arity_of o) holds
x . n in product (Carrier A,((the_arity_of o) /. n))
let A be MSAlgebra-Family of I,S; for o being OperSymbol of S
for x being Element of Args o,(product A)
for n being set st n in dom (the_arity_of o) holds
x . n in product (Carrier A,((the_arity_of o) /. n))
let o be OperSymbol of S; for x being Element of Args o,(product A)
for n being set st n in dom (the_arity_of o) holds
x . n in product (Carrier A,((the_arity_of o) /. n))
let x be Element of Args o,(product A); for n being set st n in dom (the_arity_of o) holds
x . n in product (Carrier A,((the_arity_of o) /. n))
let n be set ; ( n in dom (the_arity_of o) implies x . n in product (Carrier A,((the_arity_of o) /. n)) )
assume A1:
n in dom (the_arity_of o)
; x . n in product (Carrier A,((the_arity_of o) /. n))
dom (SORTS A) = the carrier of S
by PARTFUN1:def 4;
then
rng (the_arity_of o) c= dom (SORTS A)
;
then A2:
n in dom ((SORTS A) * (the_arity_of o))
by A1, RELAT_1:46;
x in Args o,(product A)
;
then
x in product (the Sorts of (product A) * (the_arity_of o))
by PRALG_2:10;
then
x . n in ((SORTS A) * (the_arity_of o)) . n
by A2, CARD_3:18;
then
x . n in (SORTS A) . ((the_arity_of o) . n)
by A2, FUNCT_1:22;
then
x . n in (SORTS A) . ((the_arity_of o) /. n)
by A1, PARTFUN1:def 8;
hence
x . n in product (Carrier A,((the_arity_of o) /. n))
by PRALG_2:def 17; verum