Re: recognition puzzle

*To*: mathgroup at christensen.cybernetics.net*Subject*: [mg226] Re: [mg193] recognition puzzle*From*: sfeir at mines.u-nancy.fr*Date*: Wed, 23 Nov 94 12:11:02 +0100

>Dear Mma puzzle fans: > >I have a list of several expressions; for example, > >{x^2 + 2 I x y - y^2 , 4 x^2 - 8 I x y - 4 y^2 } > >Mma has the list {x,y} of primitive variables. I want it to recognize that >these expressions are linear in only TWO cooked-up variables (namely, >x^2-y^2 and x*y), and I want it to return the list {x^2-y^2, x*y} to me. > >Is this an impossible pattern recognition task? Or is there a way to make >Mma recognize the combination x^2-y^2 by its own "thought" processes? > >Regards- Martin McClain, Chemistry, Wayne State, Deetroit The package PatternRearrange in the Mathematica Journal 4.3 by Harris addresses exactly this question. I beleive the package is also on MathSouyrce _____________________________/____________________________________ A.A. Sfeir e-mail: sfeir at mines.u-nancy.fr Ecole des Mines Tel : (33) 83 58 40 15 Parc de Saurupt (33) 83 37 64 41 54042 Nancy Cedex FRANCE Fax: (33) 83 57 97 94 _________________________________\________________________________