Comment #5 on issue 2964 by smi...@gmail.com: S.One.is_prime gives True http://code.google.com/p/sympy/issues/detail?id=2964
I don't think we should make the expensive isprime part of the assumptions system (old or new). I agree that 1 should not report as prime, but I think it would be better to let all positive integers report is_prime and is_composite as None. There are further improvements that can be made to the assumptions-based computation, e.g. `(2*Symbol('p', prime=True)).is_prime should report as False since 2 is clearly even; the following should also report as False.
var('i,j', integer=True)
(i, j)
(i*j).is_prime
Anyway, I made a counter proposal https://github.com/sympy/sympy/pull/965 -- You received this message because you are subscribed to the Google Groups "sympy-issues" group. To post to this group, send email to sympy-issues@googlegroups.com. To unsubscribe from this group, send email to sympy-issues+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sympy-issues?hl=en.
