#163 Factor errors: finite modulus, 3 vrbls

open
nobody
5
2006-09-09
2002-10-18
No

poly: (x+y+z)*(w+y+z)*(w+x+z);
factor(rat(poly)),modulus:2;
=>
Not enough choices for substitution. -- an error.

factor(rat(poly)),modulus:3 => irreducible (WRONG)

factor(rat(poly)),modulus:5 => OK
factor(rat(poly)),modulus:1031 => OK
factor(rat(poly)),modulus:1048583 => OK (but slow)

poly1: (y+x)*(z+x)*(z+x+w)*(z+y)*(z+y+w)*(z+y+x)

factor(rat(poly1)),modulus: xxx
=>
Not enough choices for substitution. -- an error.
for modulus= 2,3,5,7,11,1031,1048583

Discussion

  • Stavros Macrakis

    Logged In: YES
    user_id=588346

    factor(rat(x^5+y^5)),modulus:2 also thinks it's irreducible, but
    in fact it is = (y+x)*(y^4+x*y^3+x^2*y^2+x^3*y+x^4).

     
  • Robert Dodier

    Robert Dodier - 2006-07-01
    • labels: --> 460522
     
  • Robert Dodier

    Robert Dodier - 2006-09-09
    • labels: 460522 --> Lisp Core - Polynomials
     
  • Robert Dodier

    Robert Dodier - 2006-09-09

    Logged In: YES
    user_id=501686

    Same behavior observed in Maxima 5.9.3cvs / GCL 2.6.7 /
    Linux for all examples (both in original report and in
    comment dated 2002-10-18).

     

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