let a, b, r be real number ; for s, t being Point of (TOP-REAL 2) st s in circle a,b,r & t in circle a,b,r holds
(LSeg s,t) /\ (circle a,b,r) = {s,t}
let s, t be Point of (TOP-REAL 2); ( s in circle a,b,r & t in circle a,b,r implies (LSeg s,t) /\ (circle a,b,r) = {s,t} )
reconsider G = |[a,b]| as Point of (Euclid 2) by TOPREAL3:13;
Sphere G,r = circle a,b,r
by Th49;
then A1:
Sphere |[a,b]|,r = circle a,b,r
by Th15;
assume
( s in circle a,b,r & t in circle a,b,r )
; (LSeg s,t) /\ (circle a,b,r) = {s,t}
hence
(LSeg s,t) /\ (circle a,b,r) = {s,t}
by A1, Th35; verum