let S be OrderSortedSign; :: thesis: for X being V5() ManySortedSet of
for o being OperSymbol of S
for x being set st x in (((ParsedTerms X) # ) * the Arity of S) . o holds
x is FinSequence of TS (DTConOSA X)

let X be V5() ManySortedSet of ; :: thesis: for o being OperSymbol of S
for x being set st x in (((ParsedTerms X) # ) * the Arity of S) . o holds
x is FinSequence of TS (DTConOSA X)

let o be OperSymbol of S; :: thesis: for x being set st x in (((ParsedTerms X) # ) * the Arity of S) . o holds
x is FinSequence of TS (DTConOSA X)

let x be set ; :: thesis: ( x in (((ParsedTerms X) # ) * the Arity of S) . o implies x is FinSequence of TS (DTConOSA X) )
assume A1: x in (((ParsedTerms X) # ) * the Arity of S) . o ; :: thesis: x is FinSequence of TS (DTConOSA X)
set D = DTConOSA X;
set ar = the_arity_of o;
the Arity of S . o = the_arity_of o by MSUALG_1:def 6;
then x in product ((ParsedTerms X) * (the_arity_of o)) by A1, MSAFREE:1;
then consider f being Function such that
A2: ( x = f & dom f = dom ((ParsedTerms X) * (the_arity_of o)) & ( for y being set st y in dom ((ParsedTerms X) * (the_arity_of o)) holds
f . y in ((ParsedTerms X) * (the_arity_of o)) . y ) ) by CARD_3:def 5;
A3: dom ((ParsedTerms X) * (the_arity_of o)) = dom (the_arity_of o) by PARTFUN1:def 4;
dom (the_arity_of o) = Seg (len (the_arity_of o)) by FINSEQ_1:def 3;
then reconsider f = f as FinSequence by A2, A3, FINSEQ_1:def 2;
rng f c= TS (DTConOSA X)
proof
let a be set ; :: according to TARSKI:def 3 :: thesis: ( not a in rng f or a in TS (DTConOSA X) )
assume a in rng f ; :: thesis: a in TS (DTConOSA X)
then consider b being set such that
A4: ( b in dom f & f . b = a ) by FUNCT_1:def 5;
A5: a in ((ParsedTerms X) * (the_arity_of o)) . b by A2, A4;
reconsider b = b as Nat by A4;
((ParsedTerms X) * (the_arity_of o)) . b = (ParsedTerms X) . ((the_arity_of o) . b) by A2, A4, FUNCT_1:22
.= (ParsedTerms X) . ((the_arity_of o) /. b) by A2, A3, A4, PARTFUN1:def 8
.= ParsedTerms X,((the_arity_of o) /. b) by Def8
.= { s where s is Element of TS (DTConOSA X) : ( ex s1 being Element of S ex x being set st
( s1 <= (the_arity_of o) /. b & x in X . s1 & s = root-tree [x,s1] ) or ex o1 being OperSymbol of S st
( [o1,the carrier of S] = s . {} & the_result_sort_of o1 <= (the_arity_of o) /. b ) )
}
;
then consider e being Element of TS (DTConOSA X) such that
A6: a = e and
( ex s1 being Element of S ex x being set st
( s1 <= (the_arity_of o) /. b & x in X . s1 & e = root-tree [x,s1] ) or ex o being OperSymbol of S st
( [o,the carrier of S] = e . {} & the_result_sort_of o <= (the_arity_of o) /. b ) ) by A5;
thus a in TS (DTConOSA X) by A6; :: thesis: verum
end;
then reconsider f = f as FinSequence of TS (DTConOSA X) by FINSEQ_1:def 4;
f = x by A2;
hence x is FinSequence of TS (DTConOSA X) ; :: thesis: verum