let n be Nat; for r being real number
for e being Point of (Euclid n) st n <> 0 holds
OpenHypercube e,r c= Ball e,(r * (sqrt n))
let r be real number ; for e being Point of (Euclid n) st n <> 0 holds
OpenHypercube e,r c= Ball e,(r * (sqrt n))
let e be Point of (Euclid n); ( n <> 0 implies OpenHypercube e,r c= Ball e,(r * (sqrt n)) )
assume A1:
n <> 0
; OpenHypercube e,r c= Ball e,(r * (sqrt n))
then A2:
OpenHypercube e,((r * (sqrt n)) / (sqrt n)) c= Ball e,(r * (sqrt n))
by Th17;
(r / (sqrt n)) * (sqrt n) = r
by A1, XCMPLX_1:88;
hence
OpenHypercube e,r c= Ball e,(r * (sqrt n))
by A2, XCMPLX_1:75; verum