defpred S1[ Nat] means (0. R) |^ $1 = 0. R;
IA: S1[1] by BINOM:8;
IS: now :: thesis: for k being non zero Nat st S1[k] holds
S1[k + 1]
let k be non zero Nat; :: thesis: ( S1[k] implies S1[k + 1] )
assume IV: S1[k] ; :: thesis: S1[k + 1]
(0. R) |^ (k + 1) = (0. R) * ((0. R) |^ 1) by IV, BINOM:10;
hence S1[k + 1] ; :: thesis: verum
end;
for k being non zero Nat holds S1[k] from NAT_1:sch 10(IA, IS);
hence (0. R) |^ k = 0. R ; :: thesis: verum