A regression in Maxima 5.17.1 with limits andassumptions?

"F(x) assuming x >0" or whatever."

You can do this with piecewise functions and use existing Maxima commands.

pw([minf,'und,0,F(x),inf],x);

that returns the following equivilent statement.  So you do not need a new construct.

((F(x)-und)*signum(x)+F(x)+und)/2

Of course you need pw.mac to get this result easily.

Rich




----- Original Message ----- 
From: "Robert Dodier" <robert.dodier at gmail.com>
To: "Stavros Macrakis" <macrakis at alum.mit.edu>
Cc: "maxima mailing list" <maxima at math.utexas.edu>; "Raymond Toy" <raymond.toy at ericsson.com>
Sent: Tuesday, December 23, 2008 11:35 AM
Subject: Re: [Maxima] A regression in Maxima 5.17.1 with limits andassumptions?


On 12/23/08, Stavros Macrakis <macrakis at alum.mit.edu> wrote:

> Hmm.  That opens up an interesting can of worms in the general case.... The
> scope of asksign responses is (by default) one %i/%o interaction.  So
> perhaps something like [abs(x),asksign(x)] should return [x,pos], [0,zero],
> or [-x,neg], and not [abs(x),pos/zero/neg].  And what about [if x>0 then a
> else b, asksign(x)]? Should that re-simplify the conditional?

Since Maxima is mostly or entirely dominated by dynamic as opposed
to lexical constructs, it seems inappropriate to go back and reevaluate
or resimplify previously evaluated results.

That said, I wouldn't mind seeing a construct like "F(x) assuming x >
0" or whatever.

best

Robert
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