On Monday, 8 June 2015 22:18:09 UTC+2, Aaron Meurer wrote:
>
> My guess is that limit() doesn't look at assumptions. Also, limit
> uses real limits, not complex limits (which are much harder to work
> with algorithmically).
>
>
Apparently not even Mathematica implements complex limits:
In[1]:= Limit[1/x, x->0]
Out[1]= Infinity
In[2]:= Limit[1/x, x->0, Assumptions -> NotElement[x, Reals]]
1
Limit::cas: Warning: contradictory assumption(s) x \[NotElement] Reals && 0
< x < ---- encountered.
4096
1
Out[2]= Limit[-, x -> 0, Assumptions -> x \[NotElement] Reals]
x
I guess that SymPy's *limit( ... )* should raise an exception if the
parameter is not real. Do you agree?
The oo**zoo thing is a bug. Please open an issue in the issue tracker about
> it.
>
> Aaron Meurer
>
> On Mon, Jun 8, 2015 at 1:10 PM, Francesco Bonazzi
> <franz....@gmail.com <javascript:>> wrote:
> > Are you sure that SymPy's behaviour is well-defined?
> >
> > In [1]: z = Symbol('z', imaginary=True)
> >
> > In [2]: z.is_imaginary
> > Out[2]: True
> >
> > In [3]: z.is_real
> > Out[3]: False
> >
> > In [4]: limit(1/z, z, 0)
> > Out[4]: ∞
> >
> > In [5]: type(_)
> > Out[5]: sympy.core.numbers.Infinity
> >
> >
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