let n be non zero Nat; for X being non empty set
for S being non empty Subset-Family of X st S <> {{}} holds
Product (n,S) c= bool (Funcs ((Seg n),X))
let X be non empty set ; for S being non empty Subset-Family of X st S <> {{}} holds
Product (n,S) c= bool (Funcs ((Seg n),X))
let S be non empty Subset-Family of X; ( S <> {{}} implies Product (n,S) c= bool (Funcs ((Seg n),X)) )
assume A1:
S <> {{}}
; Product (n,S) c= bool (Funcs ((Seg n),X))
A2:
Product (n,S) c= bool (Funcs ((Seg n),(union S)))
by Th39;
union S c= union (bool X)
by ZFMISC_1:77;
then A3:
union S is non empty Subset of X
by A1, ZFMISC_1:81, SCMYCIEL:18;
( n -tuples_on X = Funcs ((Seg n),X) & n -tuples_on (union S) = Funcs ((Seg n),(union S)) )
by FINSEQ_2:93;
then
bool (Funcs ((Seg n),(union S))) c= bool (Funcs ((Seg n),X))
by A3, Th5, ZFMISC_1:67;
hence
Product (n,S) c= bool (Funcs ((Seg n),X))
by A2; verum