Re: Unwanted Recursion

*To*: mathgroup at smc.vnet.net*Subject*: [mg120060] Re: Unwanted Recursion*From*: David Bailey <dave at removedbailey.co.uk>*Date*: Thu, 7 Jul 2011 07:31:28 -0400 (EDT)*References*: <iv1a95$sjl$1@smc.vnet.net>

On 06/07/2011 10:35, Casorati wrote: > 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 see no infinite recursion: In[649]:= p[a_]:=a; In[650]:= p[a] Out[650]= a I suggest you post a specific piece of code that reproduces this problem immediately after killing the kernel. I also wonder what the real purpose of p is. David Bailey http://www.dbaileyconsultancy.co.uk