error in factor

edit

Hi, I have a problem with the factor() function: Consider the following code:

%display latex

j_00 = 1/2*(a^2 + eta)*(a^2 + zeta)/((a^2 - b^2)*(a^2 - c^2)*sqrt((a^2 + eta)*(a^2 + xi)*(a^2 + zeta)/((a^2 - b^2)*(a^2 - c^2))))

show(j_00)

j_00_simplified = j_00.canonicalize_radical().factor())

print(j_00_simplified)

As a result, I get:

1/2*sqrt(a^2 + eta)*sqrt(a^2 + zeta)/(sqrt(a^2 + xi)*sqrt(a + b)*sqrt(a + c)*sqrt(-a + b)*sqrt(-a + c))

The result is false! It should be:

1/2*sqrt(a^2 + eta)*sqrt(a^2 + zeta)/(sqrt(a^2 + xi)*sqrt(b^2-a^2)*sqrt(a^2 - c^2))

The term -a+c is wrong, it should be c-a. I think this is an error, or is there anything I don't see? If it is an error, what can I do that factor() returns the expected result?

Thank's in adcance,

Hans