Question on pattern matching

*To*: mathgroup at smc.vnet.net*Subject*: [mg47765] Question on pattern matching*From*: "Roman Green" <rgreen at mail.ru>*Date*: Mon, 26 Apr 2004 02:40:58 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

Hi, I am a very newbie in Mathematica so sorry for possibly stupid question. In the following Mathematica's output In[1]:= SetAttributes[k, Orderless] In[2]:= k[a, b, b] /. k[x_, x_, y_] -> 0 Out[2]= 0 In[3]:= k[a, b, b] /. k_[x_, x_, y_] -> 0 Out[3]= k[a, b, b] I can't understand why Mathematica can find match when applying pattern k[x_, x_, y_], but is unable with more general pattern k_[x_, x_, y_]. Thanks in advance. --- R. Green