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Topic: Another question about Factor
Replies: 13   Last Post: Nov 23, 2012 6:11 PM

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Tang Laoya

Posts: 23
Registered: 11/21/12
Re: Another question about Factor
Posted: Nov 22, 2012 6:31 PM
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Dear Dr. M. Abbasi,

Thank you very much for your kindly reply. I wish mathematica give me an express which I can code by Fortran with smallest number of floating operations. For example, if I have:

bb1 = -Det[{{1, 1, 1}, {y2, y3, y4}, {z2, z3, z4}}];

the result by mathematica is:
y3 z2 - y4 z2 - y2 z3 + y4 z3 + y2 z4 - y3 z4

I wish it output the result like this:
z2 (y3-y4) - z3 (y2-y4) + z4 (y2-y3)


What should I do?


Thanks,
Tang Laoya



On Thursday, November 22, 2012 11:52:01 PM UTC+8, Nasser M. Abbasi wrote:
> On 11/22/2012 9:19 AM, Tang Laoya wrote:
>

> > Dear all,
>
> >
>
> > I need to factor a polynomial express, however, it doesn't work, could anyone help
>
> >me to take a look at it?
>
> >
>
>
>

> >
>
> > The code:
>
> >
>
> > vv = Det[{{1, 1, 1, 1}, {x1, x2, x3, x4}, {y1, y2, y3, y4}, {z1, z2,
>
> > z3, z4}}];
>
>
>
> It is order one multivariate polynomial in x_i's, y_i's and z_i's and
>
> unity coefficients on all the terms.
>
>
>
> In[22]:= vv = Det[{{1, 1, 1, 1}, {x1, x2, x3, x4}, {y1, y2, y3, y4}, {z1, z2, z3, z4}}]
>
>
>
> Out[22]= x3*y2*z1 - x4*y2*z1 - x2*y3*z1 + x4*y3*z1 + x2*y4*z1 - x3*y4*z1 -
>
> x3*y1*z2 + x4*y1*z2 + x1*y3*z2 - x4*y3*z2 - x1*y4*z2 + x3*y4*z2 +
>
> x2*y1*z3 - x4*y1*z3 - x1*y2*z3 + x4*y2*z3 + x1*y4*z3 -
>
> x2*y4*z3 - x2*y1*z4 + x3*y1*z4 + x1*y2*z4 - x3*y2*z4 - x1*y3*z4 + x2*y3*z4
>
>
>
> In[38]:= PolynomialQ[vv,{x1,x2,x3,x4,y1,y2,y3,y4,z1,z2,z3,4}]
>
> Out[38]= True
>
>
>
> In[35]:= IrreduciblePolynomialQ[vv]
>
> Out[35]= True
>
>
>
> In[36]:= IrreduciblePolynomialQ[vv,Extension->All]
>
> Out[36]= True
>
>
>
> What Factors were you looking for? Tried in Maple also. Same result.
>
>
>
> --Nasser





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