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

+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
#   MARKUS E. LAUTENBACHER,                                               #
#      office:  Technical University Munich, Physics Department           #
#               Theoretical Physics T31, WD-8046 Garching, FRG            #
#               phone: 0049/89/3209-2398                                  #
#               INTERNET: lauten at ds0.cip.physik.tu-muenchen.de            #
#      private: Gohrenstr. 4/319, WD-8000 Muenchen 19, FRG                #
#-------------------------------------------------------------------------#
#   SIR ERNEST RUTHERFORD:  `Science is physics, and the rest is          #
#                            stamp collecting'                            #
#   Surely Rutherford (1871-1937) knew nothing about computers! ;-)       #
+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+

```

• Prev by Date: inclusion in the mailing list
• Next by Date: Re: BesselJ functions
• Previous by thread: inclusion in the mailing list
• Next by thread: Re: BesselJ functions