[ Charaterizing triangles with external bisectors ]
(c,b,a)
3
[ b^2 + a^2 - c^2 <= 0 \/ c (b^2 + a^2 - c^2)^2 < a b^2 (2 a c - (c^2 + a^2 - b^2)) ].
assume [ a > 0 /\ b > 0 /\ c > 0 /\ a < b + c /\ b < a + c /\ c < a + b ]
finish
