This has been brought up before. See https://github.com/sympy/sympy/issues/7765 and https://github.com/sympy/sympy/issues/8451. I don't remember if there was ever a good reason to keep Float('inf') as a separate object from oo.
Aaron Meurer On Wed, Feb 4, 2015 at 10:39 AM, Kevin Ventullo <[email protected]> wrote: > By the way, this is not just an intellectual curiosity: right now if you > ask Sympy what is the probability a uniform random variable on [0,1] > (defined with Uniform) is less than 0.5, you get an error which boils down > to these comparisons. See https://github.com/sympy/sympy/issues/8910 > > On Sunday, February 1, 2015 at 10:36:45 PM UTC-5, Kevin Ventullo wrote: >> >> Hi, >> >> I posted about this on GitHub but haven't gotten much of a response. >> Right now there are two seemingly mathematically equivalent notions of >> positive and negative infinity on the real line: >> >> -The singleton sympy.core.numbers.Infinity, also known as "oo" >> -Float("inf"), also known as "+inf" >> >> When trying to compare one of these to the other, we get inconsistent >> results, e.g. >> >> -oo < -inf >> >> will be left unevaluated but >> >> -inf > -oo >> >> returns False. >> >> I guess both of these should be False. However, we also have >> >> oo == x is False, but >> x == oo is True. >> >> Which of these is correct? Both of them? >> > -- > 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 http://groups.google.com/group/sympy. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/6e068b72-4c52-4b96-b01e-2a7c1bcbbe7e%40googlegroups.com > <https://groups.google.com/d/msgid/sympy/6e068b72-4c52-4b96-b01e-2a7c1bcbbe7e%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 http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6KwEmgLN6RUfY8kjVwrugE7GyAZnu6SkDAF3o%2BpBPOUKw%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
