How does a rule get applied?
- To: mathgroup@smc.vnet.net
- Subject: [mg12417] How does a rule get applied?
- From: fyaitsah@gsbux1.uchicago.edu (Yacine Ait-Sahalia)
- Date: Thu, 14 May 1998 11:15:26 -0400
- Organization: University of Chicago
Hi,
I'm having trouble understanding how rules are applied after /. Consider
the following example:
x^a + x^(1+a) /. x^(n_) + x^(n_+1) ->0
x^3 + x^(1+3) /. x^(n_) + x^(n_+1) ->0
x^3 /. x^(n_) ->0
Out[388]=
0
Out[389]=
3 4
x + x
Out[390]=
0
Could anyone please explain to me why
x^a + x^(1+a) /. x^(n_) + x^(n_+1) ->0
returns 0 (as expected), whereas
x^3 + x^(1+3) /. x^(n_) + x^(n_+1) ->0
returns
3 4
x + x
instead of 0?
Thanks for your help.