let r be real non negative number ; 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:55;
A1:
n in NAT
by ORDINAL1:def 13;
then A2:
the carrier of (Tcircle (0. (TOP-REAL n)),r) = Sphere (0. (TOP-REAL n)),r
by TOPREALB:9;
|.((- p1) - (0. (TOP-REAL n))).| =
|.(- p1).|
by RLVECT_1:26
.=
|.p1.|
by EUCLID:75
.=
|.(p1 - (0. (TOP-REAL n))).|
by RLVECT_1:26
.=
r
by A1, A2, TOPREAL9:9
;
hence
- p is Point of (Tcircle (0. (TOP-REAL n)),r)
by A2, A1, TOPREAL9:9; verum