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|    sci.math.symbolic    |    Symbolic algebra discussion    |    10,432 messages    |
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|    Message 9,960 of 10,432    |
|    Nasser M. Abbasi to clicliclic@freenet.de    |
|    Re: polynomial factoring over an algebra    |
|    05 Jul 19 02:28:30    |
      From: nma@12000.org              On 7/4/2019 12:37 PM, clicliclic@freenet.de wrote:       >       > Hello,       >       > can this trivariate polynomial:       >       > 256*a^5*c^3 - a^4*(128*b^2*c^2 - 144*b*c - 512*c^4 + 27)       > + a^3*(16*b^4*c - 4*b^3 - 512*b^2*c^3 + 208*b*c^2 + 4*c*(64*c^4 - 9))       > + 2*a^2*(80*b^4*c^2 - 82*b^3*c + b^2*(15 - 64*c^4) - 104*b*c^3 - c^2)       > - 4*a*(4*b^6*c - b^5 - 4*b^4*c^3 - 41*b^3*c^2 + 35*b^2*c       > + 6*b*(6*c^4 - 1) + 9*c^3)       > - 4*b^5*c + b^4 + 4*b^3*c^3 + 30*b^2*c^2 - 24*b*c - 27*c^4 + 4       >       > be factored over the algebraic extension combining 2^(1/4), 3^(1/8),       > and SQRT(SQRT(3) + 1)? In FriCAS one would enter:       >       > r2:=rootOf(r2^4-2)       > r3:=rootOf(r3^8-3)       > rs:=rootOf(rs^2-r3^4-1)       > factor(256*a^5*c^3 - a^4*(128*b^2*c^2 - 144*b*c - 512*c^4 + 27) +       > a^3*(16*b^4*c - 4*b^3 - 512*b^2*c^3 + 208*b*c^2 + 4*c*(64*c^4 - 9)) +       > 2*a^2*(80*b^4*c^2 - 82*b^3*c + b^2*(15 - 64*c^4) - 104*b*c^3 - c^2) -       > 4*a*(4*b^6*c - b^5 - 4*b^4*c^3 - 41*b^3*c^2 + 35*b^2*c + 6*b*(6*c^4 -       > 1) + 9*c^3) - 4*b^5*c + b^4 + 4*b^3*c^3 + 30*b^2*c^2 - 24*b*c -       > 27*c^4 + 4, [r2, r3, rs])       >       > but the web interface bumps into its 5min timeout.       >       > Martin :(.       >              on Liux it finished agfter about 8-10 minutes. But as metioned, it did       not factor to product of terms. Here is the result               (6)        "256::AlgebraicNumber()*primeFactor((1::AlgebraicNumber()*a^3       c^5+(((-1)/2)::        AlgebraicNumber()*a^2*b^2+((-9)/16)::AlgebraicNumber()*a*b+(2       :AlgebraicNumbe        r()*a^4+((-27)/256)::AlgebraicNumber()))*c^4+((1/16)::Algebra       cNumber()*a*b^4        +(1/64)::AlgebraicNumber()*b^3+(-2)::AlgebraicNumber()*a^3*b^       +((-13)/16)::Al        gebraicNumber()*a^2*b+(1::AlgebraicNumber()*a^5+((-9)/64)::Al       ebraicNumber()*        a))*c^3+((5/8)::AlgebraicNumber()*a^2*b^4+(41/64)::AlgebraicN       mber()*a*b^3+((        (-1)/2)::AlgebraicNumber()*a^4+(15/128)::AlgebraicNumber())*b       2+(13/16)::Alge        braicNumber()*a^3*b+((-1)/128)::AlgebraicNumber()*a^2)*c^2+((       -1)/16)::Algebr        aicNumber()*a*b^6+((-1)/64)::AlgebraicNumber()*b^5+(1/16)::Al       ebraicNumber()*        a^3*b^4+((-41)/64)::AlgebraicNumber()*a^2*b^3+((-35)/64)::Alg       braicNumber()*a        *b^2+((9/16)::AlgebraicNumber()*a^4+((-3)/32)::AlgebraicNumbe       ())*b+((-9)/64)        ::AlgebraicNumber()*a^3)*c+((1/64)::AlgebraicNumber()*a*b^5+(       /256)::Algebrai        cNumber()*b^4+((-1)/64)::AlgebraicNumber()*a^3*b^3+(15/128)::       lgebraicNumber(        )*a^2*b^2+(3/32)::AlgebraicNumber()*a*b+(((-27)/256)::Algebra       cNumber()*a^4+(        1/64)::AlgebraicNumber())))::Polynomial(AlgebraicNumber()),1)"              Which is hard to read, so the latex version is here              https://www.12000.org/tmp/070419/foo.pdf              --Nasser              --- SoupGate-Win32 v1.05        * Origin: you cannot sedate... all the things you hate (1:229/2)    |
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