Re: Unwanted Recursion
- To: mathgroup at smc.vnet.net
- Subject: [mg120040] Re: Unwanted Recursion
- From: Kambis Veschgini <k.veschgini at thphys.uni-heidelberg.de>
- Date: Thu, 7 Jul 2011 07:27:52 -0400 (EDT)
- References: <iv1a95$sjl$1@smc.vnet.net>
On 2011-07-06 11:35:33 +0200, Casorati said:
> I'm trying to define an anti-commutative algebra in Mathematica.
> Here I will show only a minimal example to demonstrate my point.
> The product of two elements a^b should be give by p[a,b] so I
> make p flat:
>
> SetAttributes[p, {Flat}]
>
> But now I want p[a] to reduce to a.
> Such a rule would make other rules much simpler but when I define
>
> p[a_] := a
>
> the expression p[a] causes an infinite recursion. I get the message
>
> $IterationLimit::itlim: Iteration limit of 4096 exceeded.
>
> I have similar problems with p[]:=1 which makes mathematica puts
> ones into the p : p[a]=p[a,a]=p[1,1,...,a] .
>
> How can I solve this problem?
I found out that if SetAttributes is called after the rules are defined
the recursion does not happen but I don't know why. Can someone explain
this behavior?