let a, b, r be real number ; :: thesis: inside_of_circle a,b,r misses circle a,b,r
assume
not inside_of_circle a,b,r misses circle a,b,r
; :: thesis: contradiction
then consider x being set such that
A1:
x in inside_of_circle a,b,r
and
A2:
x in circle a,b,r
by XBOOLE_0:3;
reconsider x = x as Point of (TOP-REAL 2) by A1;
|.(x - |[a,b]|).| = r
by A2, Th43;
hence
contradiction
by A1, Th45; :: thesis: verum