deffunc H1( Element of S) -> Function = proj (Carrier A,$1),i;
consider F being ManySortedSet of such that
A1: for s being Element of S holds F . s = H1(s) from PBOOLE:sch 5();
F is ManySortedFunction of (product A),(A . i)
proof
let s be set ; :: according to PBOOLE:def 18 :: thesis: ( not s in the carrier of S or F . s is Element of K10(K11((the Sorts of (product A) . s),(the Sorts of (A . i) . s))) )
assume A2: s in the carrier of S ; :: thesis: F . s is Element of K10(K11((the Sorts of (product A) . s),(the Sorts of (A . i) . s)))
F . s is Function of (the Sorts of (product A) . s),(the Sorts of (A . i) . s)
proof
reconsider s' = s as Element of S by A2;
F . s = proj (Carrier A,s'),i by A1;
then reconsider F' = F . s as Function ;
A3: not the Sorts of (A . i) . s is empty by A2;
A4: dom F' = dom (proj (Carrier A,s'),i) by A1
.= product (Carrier A,s') by Def2
.= the Sorts of (product A) . s by PRALG_2:def 17 ;
rng F' c= the Sorts of (A . i) . s
proof
let y be set ; :: according to TARSKI:def 3 :: thesis: ( not y in rng F' or y in the Sorts of (A . i) . s )
assume y in rng F' ; :: thesis: y in the Sorts of (A . i) . s
then y in rng (proj (Carrier A,s'),i) by A1;
then consider x1 being set such that
A5: x1 in dom (proj (Carrier A,s'),i) and
A6: y = (proj (Carrier A,s'),i) . x1 by FUNCT_1:def 5;
A7: x1 in product (Carrier A,s') by A5, Def2;
then reconsider x1 = x1 as Function ;
A8: dom (Carrier A,s') = I by PARTFUN1:def 4;
A9: y = x1 . i by A5, A6, Def2;
consider U0 being MSAlgebra of S such that
A10: ( U0 = A . i & (Carrier A,s') . i = the Sorts of U0 . s' ) by PRALG_2:def 16;
thus y in the Sorts of (A . i) . s by A7, A8, A9, A10, CARD_3:18; :: thesis: verum
end;
hence F . s is Function of (the Sorts of (product A) . s),(the Sorts of (A . i) . s) by A3, A4, FUNCT_2:def 1, RELSET_1:11; :: thesis: verum
end;
hence F . s is Element of K10(K11((the Sorts of (product A) . s),(the Sorts of (A . i) . s))) ; :: thesis: verum
end;
then reconsider F' = F as ManySortedFunction of (product A),(A . i) ;
take F' ; :: thesis: for s being Element of S holds F' . s = proj (Carrier A,s),i
thus for s being Element of S holds F' . s = proj (Carrier A,s),i by A1; :: thesis: verum