Re: comparing rewite rules

*To*: mathgroup at smc.vnet.net*Subject*: [mg78349] Re: comparing rewite rules*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Thu, 28 Jun 2007 06:36:08 -0400 (EDT)*Organization*: Uni Leipzig*References*: <f5vsg8$l2f$1@smc.vnet.net>*Reply-to*: kuska at informatik.uni-leipzig.de

Hi, Sort /@ ({yy -> 4, y -> 3} == {y -> 3, yy -> 4}) because you have to bring the rules into a unique order. General {a,b} is different from {b,a}, but in for a list of rules the order does not have a meaning. Regards Jens dbsearch04 at yahoo.com wrote: > Hello Mathematica UG: > > I input these 2 simple rewrite rule sets into Mathematica V5: > > - {yy -> 4, y -> 3} > > - {y -> 3, yy -> 4} > > I just want to compare these 2 simple rules for equality. I tried: > > - define each one and use % == %% (this just gives: {yy -> 4, y -> 3} > == {y -> 3, yy -> 4} ) > - making a symbol for each rule set and using ==, such as rul0 == > rul1, > it just echoes my input > > I also tried to replace the rules in an expression. If the replaced > result evaluates to a simple expression, it is OK but, it still fails > sometime when Mathematica reorders expressions, such as when x-1 becomes -1 + > x > > Is it possible to determine in my code that 2 "rule lists" are the > same? > > Of course, in the general case, I will have many more rules than just > these 2 small lists (e.g. Solve[] output). > > Thanks in advance. > > Regards..Roger > >