let r be non negative Real; for n being non zero Nat
for p being Point of (Tcircle ((0. (TOP-REAL n)),r)) holds - p is Point of (Tcircle ((0. (TOP-REAL n)),r))
let n be non zero Nat; for p being Point of (Tcircle ((0. (TOP-REAL n)),r)) holds - p is Point of (Tcircle ((0. (TOP-REAL n)),r))
let p be Point of (Tcircle ((0. (TOP-REAL n)),r)); - p is Point of (Tcircle ((0. (TOP-REAL n)),r))
reconsider p1 = p as Point of (TOP-REAL n) by PRE_TOPC:25;
n in NAT
by ORDINAL1:def 12;
then A1:
the carrier of (Tcircle ((0. (TOP-REAL n)),r)) = Sphere ((0. (TOP-REAL n)),r)
by TOPREALB:9;
|.((- p1) - (0. (TOP-REAL n))).| =
|.(- p1).|
.=
|.p1.|
by EUCLID:71
.=
|.(p1 - (0. (TOP-REAL n))).|
.=
r
by A1, TOPREAL9:9
;
hence
- p is Point of (Tcircle ((0. (TOP-REAL n)),r))
by A1, TOPREAL9:9; verum