PolynomialQ
- To: mathgroup at yoda.ncsa.uiuc.edu
- Subject: PolynomialQ
- From: Markus Lautenbacher <lauten at srv.cip.Physik.TU-Muenchen.DE>
- Date: Fri, 11 Jan 91 19:46:51 +0100
In response to jack at chopin.udel.edu (Jack Seltzer)'s "PolynomialQ"
question bc at uxa.cso.uiuc.edu (Ben Cox) writes:
> No, this is correct. PolynomialQ[expr,{x}] fails only if expr uses x in
> such a way that would forbid it (e.g., Log[x]).
> This is mathematically correct: 0 is a polynomial in x, for example.
,but then what about the following example form the MATHEMATICA book
(page 383):
>> Mathematica (sun4) 1.2 (June 13, 1990) [With pre-loaded data]
>> by S. Wolfram, D. Grayson, R. Maeder, H. Cejtin,
>> S. Omohundro, D. Ballman and J. Keiper
>> with I. Rivin and D. Withoff
>> Copyright 1988,1989,1990 Wolfram Research Inc.
>> -- X11 windows graphics initialized --
>>
>> In[1]:= t = Expand[ (1+x)^3 (1-y-x)^2 ]
>> 2 3 4 5 3 4 2
>> Out[1]= 1 + x - 2 x - 2 x + x + x - 2 y - 4 x y + 4 x y + 2 x y + y
>>
>> 2 2 2 3 2
>> > + 3 x y + 3 x y + x y
>>
>> In[2]:= PolynomialQ[t,x]
>>
>> Out[2]= True
while the book states that this should give "Out[3]= False" !.
So the "bug claim" doesn't seem to be wiped off.
MARKUS
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