defpred S1[ object , object ] means ex v being Vertex of IIG st
( v = $1 & $2 in Constants (SCS,v) );
set SW = SortsWithConstants IIG;
A1: now :: thesis: for i being object st i in SortsWithConstants IIG holds
ex y being object st S1[i,y]
let i be object ; :: thesis: ( i in SortsWithConstants IIG implies ex y being object st S1[i,y] )
A2: SortsWithConstants IIG = { v where v is SortSymbol of IIG : v is with_const_op } by MSAFREE2:def 1;
assume A3: i in SortsWithConstants IIG ; :: thesis: ex y being object st S1[i,y]
then reconsider x = i as Vertex of IIG ;
consider v being Vertex of IIG such that
A4: v = x and
A5: v is with_const_op by A3, A2;
consider o being OperSymbol of IIG such that
A6: the Arity of IIG . o = {} and
A7: the ResultSort of IIG . o = v by A5, MSUALG_2:def 1;
A8: dom the ResultSort of IIG = the carrier' of IIG by FUNCT_2:def 1;
set y = the Element of rng (Den (o,SCS));
Result (o,SCS) = ( the Sorts of SCS * the ResultSort of IIG) . o by MSUALG_1:def 5
.= the Sorts of SCS . ( the ResultSort of IIG . o) by A8, FUNCT_1:13 ;
then reconsider y9 = the Element of rng (Den (o,SCS)) as Element of the Sorts of SCS . v by A7;
reconsider y = the Element of rng (Den (o,SCS)) as object ;
take y = y; :: thesis: S1[i,y]
ex A being non empty set st
( A = the Sorts of SCS . v & Constants (SCS,v) = { a where a is Element of A : ex o being OperSymbol of IIG st
( the Arity of IIG . o = {} & the ResultSort of IIG . o = v & a in rng (Den (o,SCS)) )
}
) by MSUALG_2:def 3;
then y9 in Constants (SCS,x) by A4, A6, A7;
hence S1[i,y] ; :: thesis: verum
end;
consider f being ManySortedSet of SortsWithConstants IIG such that
A9: for i being object st i in SortsWithConstants IIG holds
S1[i,f . i] from PBOOLE:sch 3(A1);
take f ; :: thesis: for x being Vertex of IIG st x in dom f holds
f . x in Constants (SCS,x)

let x be Vertex of IIG; :: thesis: ( x in dom f implies f . x in Constants (SCS,x) )
assume x in dom f ; :: thesis: f . x in Constants (SCS,x)
then x in SortsWithConstants IIG ;
then S1[x,f . x] by A9;
hence f . x in Constants (SCS,x) ; :: thesis: verum