[GiNaC-devel] Expression comparison

Hallo, I am a GiNaC newbe and I seem not to understand expression comparisons fully, I have following test case which does not work as I expected: void testNumComparison() { Num v0 = sqrt(Num(2)); Num v1 = sqrt(Num(10)); stringstream strm; strm << "v0("<<v0<<") < v1("<<v1<<") ?"; CPPUNIT_ASSERT_MESSAGE(strm.str(),v0<v1); } Where Num is GiNaC::ex. Doing v0.evalf() < v1.evalf() works. Can somebody give me (or point me to) some info about expression comparison? Cheers and thx in advance, Peter