
theorem
for n,i be non zero Nat, X be non-empty (n+1)-element FinSequence,
    S be sigmaFieldFamily of X st i <= n holds
 CarProduct SubFin(X,i) = CarProduct SubFin(SubFin(X,n),i)
proof
    let n,i be non zero Nat, X be non-empty (n+1)-element FinSequence,
    S be sigmaFieldFamily of X;
    assume A1: i <= n;
    n <= n+1 by NAT_1:13;
    hence thesis by A1,Th7;
end;
