As long as x is generic, it seems like something like this would preserve the fidelity of original ``` >>> eq = x**2 < 0 >>> ans = Piecewise((False, Eq(im(x), 0)), (True, Eq(re(x), 0)), (x > oo, True)) ``` The both are True or False at the same values of x and they both raise a TypeError if `x -> 2 + I`. Once an assumption is placed on x, like being real, this collapses to False as expected.
On Sunday, October 1, 2017 at 11:04:48 PM UTC-5, Aaron Meurer wrote: > > True and False seem the best. It could return something like 1 = 0, but > that would just evaluate to False anyway. > > Aaron Meurer > > On Sun, Oct 1, 2017 at 11:42 PM Chris Smith <[email protected] > <javascript:>> wrote: > >> When solving an inequality that is true for all reals, e.g. `x**2 >= 0`, >> the relational (-oo < x) & (x < oo) is returned by >> `solve_univariate_inequality`. This is good because it enforces the >> condition that x be real: substitution of x with I, for example, will fail. >> But if the relationship is never true for any real numbers, S.EmptySet is >> returned and as a relational, this comes back as False. Should a relational >> like x > oo be returned instead? >> >> ``` >> >>> from sympy.abc import x >> >>> S.Reals.as_relational(x) >> (-oo < x) & (x < oo) >> >>> S.EmptySet.as_relational(x) >> False >> >>> S.UniversalSet.as_relational(x) >> True >> ``` >> >> -- >> You received this message because you are subscribed to the Google Groups >> "sympy" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected] <javascript:>. >> To post to this group, send email to [email protected] <javascript:> >> . >> Visit this group at https://groups.google.com/group/sympy. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/sympy/e01580ef-40bc-4872-9d4d-bb2156507608%40googlegroups.com >> >> <https://groups.google.com/d/msgid/sympy/e01580ef-40bc-4872-9d4d-bb2156507608%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> For more options, visit https://groups.google.com/d/optout. >> > -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/7f782b04-c441-4575-adbd-d0f7fde0ba4b%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
