(originally only responded to kcrisman...)
-------- Original Message --------
Subject: Re: [Maxima] inf and minf
Date: Thu, 15 Sep 2011 12:56:20 -0700
From: Richard Fateman <fateman at eecs.berkeley.edu>
To: Karl-Dieter Crisman <kcrisman at gmail.com>, fateman at cs.berkeley.edu
On 9/15/2011 12:44 PM, Karl-Dieter Crisman wrote:
>> Message: 5
>> Date: Thu, 15 Sep 2011 11:57:01 -0700
>> From: Richard Fateman<fateman at eecs.berkeley.edu>
>> To: Maxima - list<Maxima at math.utexas.edu>
>> Subject: inf and minf
>> Message-ID:<4E724A7D.7080802 at eecs.berkeley.edu>
>> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>>
>> Do we need minf? (negative real infinity)
>>
>> Note that - minf is currently not simplified to inf.
>>
>> RJF
>
> Is there a pressing need to remove this? It seems like it would break
> a lot of existing code (or at least cause annoyance for anyone using
> Maxima for improper integrals).
It's generally a hassle if you have two internal representations of the
same value, at least if they coexist in the same subsystem. (There are
indeed different ways of representing things because there are taylor
series, polynomials, poisson series ... that can be equivalent). But in
the general representation in maxima, 1/x is x^(-1) internally, -x is
(-1)*x etc.
I am trying to write a paper in which I mention the notion of
DirectedInfinity as in Mathematica.
ComplexInfinity is DirectedInfinity[].
real positive infinity is DirectedInfinity[1]
negative is DirectedInfinity[-1]
and any point on the unit circle can denote a particular direction as
argument to DirectedInfinity.
-DirectedInfinity[1] is simplified to DirectedInfinity[-1].
The analogous simplification is not done in Maxima.
That's probably a misfeature. I wonder if Maxima really needs minf.
other than seeing - - oo in wxmaxima, I have no specific issue.
RJF