theorem Th24:
for
r being
Real holds
(
inside_of_circle (
0,
0,
r)
= { p where p is Point of (TOP-REAL 2) : |.p.| < r } & (
r > 0 implies
circle (
0,
0,
r)
= { p2 where p2 is Point of (TOP-REAL 2) : |.p2.| = r } ) &
outside_of_circle (
0,
0,
r)
= { p3 where p3 is Point of (TOP-REAL 2) : |.p3.| > r } &
closed_inside_of_circle (
0,
0,
r)
= { q where q is Point of (TOP-REAL 2) : |.q.| <= r } &
closed_outside_of_circle (
0,
0,
r)
= { q2 where q2 is Point of (TOP-REAL 2) : |.q2.| >= r } )