let a, b, r be Real; circle (a,b,r) c= closed_inside_of_circle (a,b,r)
let x be object ; TARSKI:def 3 ( not x in circle (a,b,r) or x in closed_inside_of_circle (a,b,r) )
assume A1:
x in circle (a,b,r)
; x in closed_inside_of_circle (a,b,r)
then reconsider x = x as Point of (TOP-REAL 2) ;
|.(x - |[a,b]|).| = r
by A1, Th41;
hence
x in closed_inside_of_circle (a,b,r)
by Th42; verum