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Diff for /OpenXM/src/asir-doc/parts/groebner.texi between version 1.4 and 1.5

version 1.4, 2003/04/19 15:44:56

version 1.5, 2003/04/20 08:01:25

Line 1

@comment $OpenXM: OpenXM/src/asir-doc/parts/groebner.texi,v 1.3 1999/12/24 04:38:04 noro Exp $

@comment $OpenXM: OpenXM/src/asir-doc/parts/groebner.texi,v 1.4 2003/04/19 15:44:56 noro Exp $

\BJP

@node $B%0%l%V%J4pDl$N7W;;(B,,, Top

@chapter $B%0%l%V%J4pDl$N7W;;(B

Line 17

* $B9`=g=x$N@_Dj(B::

* $BM-M}<0$r78?t$H$9$k%0%l%V%J4pDl7W;;(B::

* $B4pDlJQ49(B::

* Weyl $BBe?t(B::

* $B%0%l%V%J4pDl$K4X$9$kH!?t(B::

\BEG

Line 27

Line 28

* Setting term orderings::

* Groebner basis computation with rational function coefficients::

* Change of ordering::

* Weyl algebra::

* Functions for Groebner basis computation::

@end menu

Line 228 the head term and the head coefficient respectively.

Line 230 the head term and the head coefficient respectively.

@noindent

\BJP

$B%0%l%V%J4pDl$r7W;;$9$k$?$a$N4pK\E*$JH!?t$O(B @code{dp_gr_main()} $B$*$h$S(B

@code{dp_gr_mod_main()} $B$J$k(B 2 $B$D$NAH$_9~$_H!?t$G$"$k$,(B, $BDL>o$O(B, $B%Q%i%a%?(B

@code{dp_gr_mod_main()}, @code{dp_gr_f_main()}

$B$J$k(B 3 $B$D$NAH$_9~$_H!?t$G$"$k$,(B, $BDL>o$O(B, $B%Q%i%a%?(B

$B@_Dj$J$I$r9T$C$?$N$A$3$l$i$r8F$S=P$9%f!<%6H!?t$rMQ$$$k$N$,JXMx$G$"$k(B.

$B$3$l$i$N%f!<%6H!?t$O(B, $B%U%!%$%k(B @samp{gr} $B$r(B @code{load()} $B$K$h$jFI(B

$B$_9~$`$3$H$K$h$j;HMQ2DG=$H$J$k(B. @samp{gr} $B$O(B, @b{Asir} $B$NI8=`(B

$B%i%$%V%i%j%G%#%l%/%H%j$KCV$+$l$F$$$k(B. $B$h$C$F(B, $B4D6-JQ?t(B @code{ASIR_LIBDIR}

$B%i%$%V%i%j%G%#%l%/%H%j$KCV$+$l$F$$$k(B.

$B$rFC$K0[$J$k%Q%9$K@_Dj$7$J$$8B$j(B, $B%U%!%$%kL>$N$_$GFI$_9~$`$3$H$,$G$-$k(B.

\BEG

Facilities for computing Groebner bases are provided not by built-in

Facilities for computing Groebner bases are

functions but by a set of user functions written in @b{Asir}.

@code{dp_gr_main()}, @code{dp_gr_mod_main()}and @code{dp_gr_f_main()}.

The set of functions is provided as a file (sometimes called package),

To call these functions,

named @samp{gr}.

it is necessary to set several parameters correctly and it is convenient

to use a set of interface functions provided in the library file

@samp{gr}.

The facilities will be ready to use after you load the package by

@code{load()}. The package @samp{gr} is placed in the standard library

directory of @b{Asir}. Therefore, it is loaded simply by specifying

directory of @b{Asir}.

its file name, unless the environment variable @code{ASIR_LIBDIR}

is set to a non-standard one.

@example

Line 350 These parameters can be set and examined by a built-in

Line 352 These parameters can be set and examined by a built-in

@example

[100] dp_gr_flags();

[Demand,0,NoSugar,0,NoCriB,0,NoGC,0,NoMC,0,NoRA,0,NoGCD,0,Top,0,ShowMag,1,

[Demand,0,NoSugar,0,NoCriB,0,NoGC,0,NoMC,0,NoRA,0,NoGCD,0,Top,0,

Print,1,Stat,0,Reverse,0,InterReduce,0,Multiple,0]

ShowMag,1,Print,1,Stat,0,Reverse,0,InterReduce,0,Multiple,0]

[101]

@end example

Line 530 membercheck

Line 532 membercheck

(0,0)(0,0)(0,0)(0,0)

gbcheck total 8 pairs

........

UP=(0,0)SP=(0,0)SPM=(0,0)NF=(0,0)NFM=(0.010002,0)ZNFM=(0.010002,0)PZ=(0,0)

UP=(0,0)SP=(0,0)SPM=(0,0)NF=(0,0)NFM=(0.010002,0)ZNFM=(0.010002,0)

NP=(0,0)MP=(0,0)RA=(0,0)MC=(0,0)GC=(0,0)T=40,B=0 M=8 F=6 D=12 ZR=5 NZR=6

PZ=(0,0)NP=(0,0)MP=(0,0)RA=(0,0)MC=(0,0)GC=(0,0)T=40,B=0 M=8 F=6

Max_mag=6

D=12 ZR=5 NZR=6 Max_mag=6

[94]

@end example

Line 992 time as well as the choice of types of term orderings.

Line 994 time as well as the choice of types of term orderings.

-40*t^8+70*t^7+252*t^6+30*t^5-140*t^4-168*t^3+2*t^2-12*t+16)*z^2*y

+(-12*t^16+72*t^13-28*t^11-180*t^10+112*t^8+240*t^7+28*t^6-127*t^5

-167*t^4-55*t^3+30*t^2+58*t-15)*z^4,

(y+t^2*z^2)*x+y^7+(20*t^2+6*t+1)*y^2+(-t^17+6*t^14-21*t^12-15*t^11+84*t^9

(y+t^2*z^2)*x+y^7+(20*t^2+6*t+1)*y^2+(-t^17+6*t^14-21*t^12-15*t^11

+20*t^8-35*t^7-126*t^6-15*t^5+70*t^4+84*t^3-t^2+5*t-9)*z^2*y+(6*t^16-36*t^13

+84*t^9+20*t^8-35*t^7-126*t^6-15*t^5+70*t^4+84*t^3-t^2+5*t-9)*z^2*y

+14*t^11+90*t^10-56*t^8-120*t^7-14*t^6+64*t^5+84*t^4+27*t^3-16*t^2-30*t+7)*z^4,

+(6*t^16-36*t^13+14*t^11+90*t^10-56*t^8-120*t^7-14*t^6+64*t^5+84*t^4

(t^3-1)*x-y^6+(-6*t^13+24*t^10-20*t^8-36*t^7+40*t^5+24*t^4-6*t^3-20*t^2-6*t-1)*y

+27*t^3-16*t^2-30*t+7)*z^4,

+(t^17-6*t^14+9*t^12+15*t^11-36*t^9-20*t^8-5*t^7+54*t^6+15*t^5+10*t^4-36*t^3

(t^3-1)*x-y^6+(-6*t^13+24*t^10-20*t^8-36*t^7+40*t^5+24*t^4-6*t^3-20*t^2

-11*t^2-5*t+9)*z^2,

-6*t-1)*y+(t^17-6*t^14+9*t^12+15*t^11-36*t^9-20*t^8-5*t^7+54*t^6+15*t^5

+10*t^4-36*t^3-11*t^2-5*t+9)*z^2,

-y^8-8*t*y^3+16*z^2*y^2+(-8*t^16+48*t^13-56*t^11-120*t^10+224*t^8+160*t^7

-56*t^6-336*t^5-112*t^4+112*t^3+224*t^2+24*t-56)*z^4*y+(t^24-8*t^21+20*t^19

-56*t^6-336*t^5-112*t^4+112*t^3+224*t^2+24*t-56)*z^4*y+(t^24-8*t^21

+28*t^18-120*t^16-56*t^15+14*t^14+300*t^13+70*t^12-56*t^11-400*t^10-84*t^9

+20*t^19+28*t^18-120*t^16-56*t^15+14*t^14+300*t^13+70*t^12-56*t^11

+84*t^8+268*t^7+84*t^6-56*t^5-63*t^4-36*t^3+46*t^2-12*t+1)*z,

-400*t^10-84*t^9+84*t^8+268*t^7+84*t^6-56*t^5-63*t^4-36*t^3+46*t^2

2*t*y^5+z*y^2+(-2*t^11+8*t^8-20*t^6-12*t^5+40*t^3+8*t^2-10*t-20)*z^3*y+8*t^14

-12*t+1)*z,2*t*y^5+z*y^2+(-2*t^11+8*t^8-20*t^6-12*t^5+40*t^3+8*t^2

-32*t^11+48*t^8-t^7-32*t^5-6*t^4+9*t^2-t,

-10*t-20)*z^3*y+8*t^14-32*t^11+48*t^8-t^7-32*t^5-6*t^4+9*t^2-t,

-z*y^3+(t^7-2*t^4+3*t^2+t)*y+(-2*t^6+4*t^3+2*t-2)*z^2,

2*t^2*y^3+z^2*y^2+(-2*t^5+4*t^2-6)*z^4*y+(4*t^8-t^7-8*t^5+2*t^4-4*t^3+5*t^2-t)*z,

2*t^2*y^3+z^2*y^2+(-2*t^5+4*t^2-6)*z^4*y

+(4*t^8-t^7-8*t^5+2*t^4-4*t^3+5*t^2-t)*z,

z^3*y^2+2*t^3*y+(-t^7+2*t^4+t^2-t)*z^2,

-t*z*y^2-2*z^3*y+t^8-2*t^5-t^3+t^2,

-t^3*y^2-2*t^2*z^2*y+(t^6-2*t^3-t+1)*z^4,

-t^3*y^2-2*t^2*z^2*y+(t^6-2*t^3-t+1)*z^4,z^5-t^4]

z^5-t^4]

[93] gr(B,[t,z,y,x],2);

[x^10-t,x^8-z,x^31-x^6-x-y]

@end example

Line 1214 Refer to the sections for each functions.

Line 1217 Refer to the sections for each functions.

* lex_hensel_gsl tolex_gsl tolex_gsl_d::

* gr_minipoly minipoly::

* tolexm minipolym::

* dp_gr_main dp_gr_mod_main::

* dp_gr_main dp_gr_mod_main dp_gr_f_main::

* dp_f4_main dp_f4_mod_main::

* dp_gr_flags dp_gr_print::

* dp_ord::

Line 1240 Refer to the sections for each functions.

Line 1243 Refer to the sections for each functions.

* dp_vtoe dp_etov::

* lex_hensel_gsl tolex_gsl tolex_gsl_d::

* primadec primedec::

* primedec_mod::

@end menu

\JP @node gr hgr gr_mod,,, $B%0%l%V%J4pDl$K4X$9$kH!?t(B

Line 1342 for communication.

Line 1346 for communication.

@table @t

\JP @item $B;2>H(B

\EG @item References

@comment @fref{dp_gr_main dp_gr_mod_main},

@comment @fref{dp_gr_main dp_gr_mod_main dp_gr_f_main},

@fref{dp_gr_main dp_gr_mod_main},

@fref{dp_gr_main dp_gr_mod_main dp_gr_f_main},

@fref{dp_ord}.

@end table

Line 1560 processes.

Line 1564 processes.

@table @t

\JP @item $B;2>H(B

\EG @item References

@fref{dp_gr_main dp_gr_mod_main},

@fref{dp_gr_main dp_gr_mod_main dp_gr_f_main},

\JP @fref{dp_ord}, @fref{$BJ,;67W;;(B}

\EG @fref{dp_ord}, @fref{Distributed computation}

@end table

Line 1662 processes.

Line 1666 processes.

[108] GSL[1];

[u2,10352277157007342793600000000*u0^31-...]

[109] GSL[5];

[u0,11771021876193064124640000000*u0^32-...,376672700038178051988480000000*u0^31-...]

[u0,11771021876193064124640000000*u0^32-...,

376672700038178051988480000000*u0^31-...]

@end example

@table @t

Line 1837 z^32+11405*z^31+20868*z^30+21602*z^29+...

Line 1842 z^32+11405*z^31+20868*z^30+21602*z^29+...

@fref{gr_minipoly minipoly}.

@end table

\JP @node dp_gr_main dp_gr_mod_main,,, $B%0%l%V%J4pDl$K4X$9$kH!?t(B

\JP @node dp_gr_main dp_gr_mod_main dp_gr_f_main,,, $B%0%l%V%J4pDl$K4X$9$kH!?t(B

\EG @node dp_gr_main dp_gr_mod_main,,, Functions for Groebner basis computation

\EG @node dp_gr_main dp_gr_mod_main dp_gr_f_main,,, Functions for Groebner basis computation

@subsection @code{dp_gr_main}, @code{dp_gr_mod_main}

@subsection @code{dp_gr_main}, @code{dp_gr_mod_main}, @code{dp_gr_f_main}

@findex dp_gr_main

@findex dp_gr_mod_main

@findex dp_gr_f_main

@table @t

@item dp_gr_main(@var{plist},@var{vlist},@var{homo},@var{modular},@var{order})

@itemx dp_gr_mod_main(@var{plist},@var{vlist},@var{homo},@var{modular},@var{order})

@itemx dp_gr_f_main(@var{plist},@var{vlist},@var{homo},@var{order})

\JP :: $B%0%l%V%J4pDl$N7W;;(B ($BAH$_9~$_H!?t(B)

\EG :: Groebner basis computation (built-in functions)

@end table

Line 1875 z^32+11405*z^31+20868*z^30+21602*z^29+...

Line 1882 z^32+11405*z^31+20868*z^30+21602*z^29+...

@code{hgr()}, @code{gr_mod()} $B$J$I$O$9$Y$F$3$l$i$NH!?t$r8F$S=P$7$F7W;;(B

$B$r9T$C$F$$$k(B.

@item

@code{dp_gr_f_main()} $B$O(B, $B<o!9$NM-8BBN>e$N%0%l%V%J4pDl$r7W;;$9$k(B

$B>l9g$KMQ$$$k(B. $BF~NO$O(B, $B$"$i$+$8$a(B, @code{simp_ff()} $B$J$I$G(B,

$B9M$($kM-8BBN>e$K<M1F$5$l$F$$$kI,MW$,$"$k(B.

@item

$B%U%i%0(B @var{homo} $B$,(B 0 $B$G$J$$;~(B, $BF~NO$r@F<!2=$7$F$+$i(B Buchberger $B%"%k%4%j%:%`(B

$B$r<B9T$9$k(B.

@item

Line 1908 These functions are fundamental built-in functions for

Line 1919 These functions are fundamental built-in functions for

computation and @code{gr()},@code{hgr()} and @code{gr_mod()}

are all interfaces to these functions.

@item

@code{dp_gr_f_main()} is a function for Groebner basis computation

over various finite fields. Coefficients of input polynomials

must be converted to elements of a finite field

currently specified by @code{setmod_ff()}.

@item

If @var{homo} is not equal to 0, homogenization is applied before entering

Buchberger algorithm

@item

Line 1945 Actual computation is controlled by various parameters

Line 1961 Actual computation is controlled by various parameters

@fref{dp_ord},

@fref{dp_gr_flags dp_gr_print},

@fref{gr hgr gr_mod},

@fref{setmod_ff},

\JP @fref{$B7W;;$*$h$SI=<($N@)8f(B}.

\EG @fref{Controlling Groebner basis computations}

@end table

Line 2036 and showing informations.

Line 2053 and showing informations.

@itemize @bullet

\BJP

@item

@code{dp_gr_main()}, @code{dp_gr_mod_main()} $B<B9T;~$K$*$1$k$5$^$6$^(B

@code{dp_gr_main()}, @code{dp_gr_mod_main()}, @code{dp_gr_f_main()} $B<B9T;~$K$*$1$k$5$^$6$^(B

$B$J%Q%i%a%?$r@_Dj(B, $B;2>H$9$k(B.

@item

$B0z?t$,$J$$>l9g(B, $B8=:_$N@_Dj$,JV$5$l$k(B.

Line 2212 the coefficient field.

Line 2229 the coefficient field.

(1)*<<2,0,0>>+(2)*<<1,1,0>>+(1)*<<0,2,0>>+(2)*<<1,0,1>>+(2)*<<0,1,1>>

+(1)*<<0,0,2>>

[52] dp_ptod((x+y+z)^2,[x,y]);

(1)*<<2,0>>+(2)*<<1,1>>+(1)*<<0,2>>+(2*z)*<<1,0>>+(2*z)*<<0,1>>+(z^2)*<<0,0>>

(1)*<<2,0>>+(2)*<<1,1>>+(1)*<<0,2>>+(2*z)*<<1,0>>+(2*z)*<<0,1>>

+(z^2)*<<0,0>>

@end example

@table @t

Line 2264 variables of @var{dpoly}.

Line 2282 variables of @var{dpoly}.

@example

[53] T=dp_ptod((x+y+z)^2,[x,y]);

(1)*<<2,0>>+(2)*<<1,1>>+(1)*<<0,2>>+(2*z)*<<1,0>>+(2*z)*<<0,1>>+(z^2)*<<0,0>>

(1)*<<2,0>>+(2)*<<1,1>>+(1)*<<0,2>>+(2*z)*<<1,0>>+(2*z)*<<0,1>>

+(z^2)*<<0,0>>

[54] P=dp_dtop(T,[a,b]);

z^2+(2*a+2*b)*z+a^2+2*b*a+b^2

@end example

Line 2617 For single computation @code{p_nf} and @code{p_true_nf

Line 2636 For single computation @code{p_nf} and @code{p_true_nf

[74] DP2=newvect(length(G),map(dp_ptod,G,V))$

[75] T=dp_ptod((u0-u1+u2-u3+u4)^2,V)$

[76] dp_dtop(dp_nf([0,1,2,3,4],T,DP1,1),V);

u4^2+(6*u3+2*u2+6*u1-2)*u4+9*u3^2+(6*u2+18*u1-6)*u3+u2^2+(6*u1-2)*u2+9*u1^2-6*u1+1

u4^2+(6*u3+2*u2+6*u1-2)*u4+9*u3^2+(6*u2+18*u1-6)*u3+u2^2

+(6*u1-2)*u2+9*u1^2-6*u1+1

[77] dp_dtop(dp_nf([4,3,2,1,0],T,DP1,1),V);

-5*u4^2+(-4*u3-4*u2-4*u1)*u4-u3^2-3*u3-u2^2+(2*u1-1)*u2-2*u1^2-3*u1+1

[78] dp_dtop(dp_nf([0,1,2,3,4],T,DP2,1),V);

-1138087976845165778088612297273078520347097001020471455633353049221045677593

-11380879768451657780886122972730785203470970010204714556333530492210

0005716505560062087150928400876150217079820311439477560587583488*u4^15+...

456775930005716505560062087150928400876150217079820311439477560587583

488*u4^15+...

[79] dp_dtop(dp_nf([4,3,2,1,0],T,DP2,1),V);

-1138087976845165778088612297273078520347097001020471455633353049221045677593

-11380879768451657780886122972730785203470970010204714556333530492210

0005716505560062087150928400876150217079820311439477560587583488*u4^15+...

456775930005716505560062087150928400876150217079820311439477560587583

488*u4^15+...

[80] @@78==@@79;

@end example

Line 3170 The result is a list @code{[@var{a dpoly1},@var{a dpol

Line 3192 The result is a list @code{[@var{a dpoly1},@var{a dpol

[159] C=12*<<1,1,1,0,0>>+(1)*<<0,1,1,1,0>>+(1)*<<1,1,0,0,1>>;

(12)*<<1,1,1,0,0>>+(1)*<<0,1,1,1,0>>+(1)*<<1,1,0,0,1>>

[160] dp_red(D,R,C);

[(6)*<<2,1,0,0,0>>+(6)*<<1,2,0,0,0>>+(2)*<<0,3,0,0,0>>,(-1)*<<0,1,1,1,0>>

[(6)*<<2,1,0,0,0>>+(6)*<<1,2,0,0,0>>+(2)*<<0,3,0,0,0>>,

+(-1)*<<1,1,0,0,1>>]

(-1)*<<0,1,1,1,0>>+(-1)*<<1,1,0,0,1>>]

@end example

@table @t

Line 3409 exists.

Line 3431 exists.

@example

[233] G=gr(katsura(5),[u5,u4,u3,u2,u1,u0],2)$

[234] p_terms(G[0],[u5,u4,u3,u2,u1,u0],2);

[u5,u0^31,u0^30,u0^29,u0^28,u0^27,u0^26,u0^25,u0^24,u0^23,u0^22,u0^21,u0^20,

[u5,u0^31,u0^30,u0^29,u0^28,u0^27,u0^26,u0^25,u0^24,u0^23,u0^22,

u0^19,u0^18,u0^17,u0^16,u0^15,u0^14,u0^13,u0^12,u0^11,u0^10,u0^9,u0^8,u0^7,

u0^21,u0^20,u0^19,u0^18,u0^17,u0^16,u0^15,u0^14,u0^13,u0^12,u0^11,

u0^6,u0^5,u0^4,u0^3,u0^2,u0,1]

u0^10,u0^9,u0^8,u0^7,u0^6,u0^5,u0^4,u0^3,u0^2,u0,1]

@end example

\JP @node gb_comp,,, $B%0%l%V%J4pDl$K4X$9$kH!?t(B

Line 3519 Polynomial set @code{cyclic} is sometimes called by ot

Line 3541 Polynomial set @code{cyclic} is sometimes called by ot

[79] load("cyclic")$

[89] katsura(5);

[u0+2*u4+2*u3+2*u2+2*u1+2*u5-1,2*u4*u0-u4+2*u1*u3+u2^2+2*u5*u1,

2*u3*u0+2*u1*u4-u3+(2*u1+2*u5)*u2,2*u2*u0+2*u2*u4+(2*u1+2*u5)*u3-u2+u1^2,

2*u3*u0+2*u1*u4-u3+(2*u1+2*u5)*u2,2*u2*u0+2*u2*u4+(2*u1+2*u5)*u3

2*u1*u0+(2*u3+2*u5)*u4+2*u2*u3+2*u1*u2-u1,

-u2+u1^2,2*u1*u0+(2*u3+2*u5)*u4+2*u2*u3+2*u1*u2-u1,

u0^2-u0+2*u4^2+2*u3^2+2*u2^2+2*u1^2+2*u5^2]

[90] hkatsura(5);

[-t+u0+2*u4+2*u3+2*u2+2*u1+2*u5,

Line 3642 if an input ideal is not radical.

Line 3664 if an input ideal is not radical.

\JP @fref{$B9`=g=x$N@_Dj(B}.

\EG @fref{Setting term orderings}.

@end table

\BJP

@node Weyl $BBe?t(B,,, $B%0%l%V%J4pDl$N7W;;(B

@section Weyl $BBe?t(B

\BEG

@node Weyl algebra,,, Groebner basis computation

@section Weyl algebra

@noindent

\BJP

$B$3$l$^$G$O(B, $BDL>o$N2D49$JB?9`<04D$K$*$1$k%0%l%V%J4pDl7W;;$K$D$$$F(B

$B=R$Y$F$-$?$,(B, $B%0%l%V%J4pDl$NM}O@$O(B, $B$"$k>r7o$rK~$?$9Hs2D49$J(B

$B4D$K$b3HD%$G$-$k(B. $B$3$N$h$&$J4D$NCf$G(B, $B1~MQ>e$b=EMW$J(B,

Weyl $BBe?t(B, $B$9$J$o$AB?9`<04D>e$NHyJ,:nMQAG4D$N1i;;$*$h$S(B

$B%0%l%V%J4pDl7W;;$,(B Risa/Asir $B$K<BAu$5$l$F$$$k(B.

$BBN(B @code{K} $B>e$N(B @code{n} $B<!85(B Weyl $BBe?t(B

@code{D=K<x1,@dots{},xn,D1,@dots{},Dn>} $B$O(B

\BEG

So far we have explained Groebner basis computation in

commutative polynomial rings. However Groebner basis can be

considered in more general non-commutative rings.

Weyl algebra is one of such rings and

Risa/Asir implements fundamental operations

in Weyl algebra and Groebner basis computation in Weyl algebra.

The @code{n} dimensional Weyl algebra over a field @code{K},

@code{D=K<x1,@dots{},xn,D1,@dots{},Dn>} is a non-commutative

algebra which has the following fundamental relations:

@code{xi*xj-xj*xi=0}, @code{Di*Dj-Dj*Di=0}, @code{Di*xj-xj*Di=0} (@code{i!=j}),

@code{Di*xi-xi*Di=1}

\BJP

$B$H$$$&4pK\4X78$r;}$D4D$G$"$k(B. @code{D} $B$O(B $BB?9`<04D(B @code{K[x1,@dots{},xn]} $B$r78?t(B

$B$H$9$kHyJ,:nMQAG4D$G(B, @code{Di} $B$O(B @code{xi} $B$K$h$kHyJ,$rI=$9(B. $B8r494X78$K$h$j(B,

@code{D} $B$N85$O(B, @code{x1^i1*@dots{}*xn^in*D1^j1*@dots{}*Dn^jn} $B$J$kC19`(B

$B<0$N(B @code{K} $B@~7A7k9g$H$7$F=q$-I=$9$3$H$,$G$-$k(B.

Risa/Asir $B$K$*$$$F$O(B, $B$3$NC19`<0$r(B, $B2D49$JB?9`<0$HF1MM$K(B

@code{<<i1,@dots{},in,j1,@dots{},jn>>} $B$GI=$9(B. $B$9$J$o$A(B, @code{D} $B$N85$b(B

$BJ,;6I=8=B?9`<0$H$7$FI=$5$l$k(B. $B2C8:;;$O(B, $B2D49$N>l9g$HF1MM$K(B, @code{+}, @code{-}

$B$K$h$j(B

$B<B9T$G$-$k$,(B, $B>h;;$O(B, $BHs2D49@-$r9MN8$7$F(B @code{dp_weyl_mul()} $B$H$$$&4X?t(B

$B$K$h$j<B9T$9$k(B.

\BEG

@code{D} is the ring of differential operators whose coefficients

are polynomials in @code{K[x1,@dots{},xn]} and

@code{Di} denotes the differentiation with respect to @code{xi}.

According to the commutation relation,

elements of @code{D} can be represented as a @code{K}-linear combination

of monomials @code{x1^i1*@dots{}*xn^in*D1^j1*@dots{}*Dn^jn}.

In Risa/Asir, this type of monomial is represented

by @code{<<i1,@dots{},in,j1,@dots{},jn>>} as in the case of commutative

polynomial.

That is, elements of @code{D} are represented by distributed polynomials.

Addition and subtraction can be done by @code{+}, @code{-},

but multiplication is done by calling @code{dp_weyl_mul()} because of

the non-commutativity of @code{D}.

@example

[0] A=<<1,2,2,1>>;

(1)*<<1,2,2,1>>

[1] B=<<2,1,1,2>>;

(1)*<<2,1,1,2>>

[2] A*B;

(1)*<<3,3,3,3>>

[3] dp_weyl_mul(A,B);

(1)*<<3,3,3,3>>+(1)*<<3,2,3,2>>+(4)*<<2,3,2,3>>+(4)*<<2,2,2,2>>

+(2)*<<1,3,1,3>>+(2)*<<1,2,1,2>>

@end example

\BJP

$B%0%l%V%J4pDl7W;;$K$D$$$F$b(B, Weyl $BBe?t@lMQ$N4X?t$H$7$F(B,

$B<!$N4X?t$,MQ0U$7$F$"$k(B.

\BEG

The following functions are avilable for Groebner basis computation

in Weyl algebra:

@code{dp_weyl_gr_main()},

@code{dp_weyl_gr_mod_main()},

@code{dp_weyl_gr_f_main()},

@code{dp_weyl_f4_main()},

@code{dp_weyl_f4_mod_main()}.

\BJP

$B$^$?(B, $B1~MQ$H$7$F(B, global b $B4X?t$N7W;;$,<BAu$5$l$F$$$k(B.

\BEG

Computation of the global b function is implemented as an application.

\JP @node primedec_mod,,, $B%0%l%V%J4pDl$K4X$9$kH!?t(B

\EG @node primedec_mod,,, Functions for Groebner basis computation

@subsection @code{primedec_mod}

@findex primedec_mod

@table @t

@item primedec_mod(@var{plist},@var{vlist},@var{ord},@var{mod},@var{strategy})

\JP :: $B%$%G%"%k$NJ,2r(B

\EG :: Computes decompositions of ideals over small finite fields.

@end table

@table @var

@item return

@itemx plist

\JP $BB?9`<0%j%9%H(B

\EG list of polynomials

@item vlist

\JP $BJQ?t%j%9%H(B

\EG list of variables

@item ord

\JP $B?t(B, $B%j%9%H$^$?$O9TNs(B

\EG number, list or matrix

@item mod

\JP $B@5@0?t(B

\EG positive integer

@item strategy

\JP $B@0?t(B

\EG integer

@end table

@itemize @bullet

\BJP

@item

@code{primedec_mod()} $B$O(B @samp{primdec_mod}

$B$GDj5A$5$l$F$$$k(B. @code{[Yokoyama]} $B$NAG%$%G%"%kJ,2r%"%k%4%j%:%`(B

$B$r<BAu$7$F$$$k(B.

@item

@code{primedec_mod()} $B$OM-8BBN>e$G$N%$%G%"%k$N(B

$B:,4p$NAG%$%G%"%kJ,2r$r9T$$(B, $BAG%$%G%"%k$N%j%9%H$rJV$9(B.

@item

@code{primedec_mod()} $B$O(B, GF(@var{mod}) $B>e$G$NJ,2r$rM?$($k(B.

$B7k2L$N3F@.J,$N@8@.85$O(B, $B@0?t78?tB?9`<0$G$"$k(B.

@item

$B7k2L$K$*$$$F(B, $BB?9`<0%j%9%H$H$7$FI=<($5$l$F$$$k3F%$%G%"%k$OA4$F(B

[@var{vlist},@var{ord}] $B$G;XDj$5$l$k9`=g=x$K4X$9$k%0%l%V%J4pDl$G$"$k(B.

@item

@var{strategy} $B$,(B 0 $B$G$J$$$H$-(B, incremental $B$K(B component $B$N6&DL(B

$BItJ,$r7W;;$9$k$3$H$K$h$k(B early termination $B$r9T$&(B. $B0lHL$K(B,

$B%$%G%"%k$N<!85$,9b$$>l9g$KM-8z$@$,(B, 0 $B<!85$N>l9g$J$I(B, $B<!85$,>.$5$$(B

$B>l9g$K$O(B overhead $B$,Bg$-$$>l9g$,$"$k(B.

\BEG

@item

Function @code{primedec_mod()}

is defined in @samp{primdec_mod} and implements the prime decomposition

algorithm in @code{[Yokoyama]}.

@item

@code{primedec_mod()}

is the function for prime ideal decomposition

of the radical of a polynomial ideal over small finite field,

and they return a list of prime ideals, which are associated primes

of the input ideal.

@item

@code{primedec_mod()} gives the decomposition over GF(@var{mod}).

The generators of each resulting component consists of integral polynomials.

@item

Each resulting component is a Groebner basis with respect to

a term order specified by [@var{vlist},@var{ord}].

@item

If @var{strategy} is non zero, then the early termination strategy

is tried by computing the intersection of obtained components

incrementally. In general, this strategy is useful when the krull

dimension of the ideal is high, but it may add some overhead

if the dimension is small.

@end itemize

@example

[0] load("primdec_mod")$

[246] PP444=[x^8+x^2+t,y^8+y^2+t,z^8+z^2+t]$

[247] primedec_mod(PP444,[x,y,z,t],0,2,1);

[[y+z,x+z,z^8+z^2+t],[x+y,y^2+y+z^2+z+1,z^8+z^2+t],

[y+z+1,x+z+1,z^8+z^2+t],[x+z,y^2+y+z^2+z+1,z^8+z^2+t],

[y+z,x^2+x+z^2+z+1,z^8+z^2+t],[y+z+1,x^2+x+z^2+z+1,z^8+z^2+t],

[x+z+1,y^2+y+z^2+z+1,z^8+z^2+t],[y+z+1,x+z,z^8+z^2+t],

[x+y+1,y^2+y+z^2+z+1,z^8+z^2+t],[y+z,x+z+1,z^8+z^2+t]]

[248]

@end example

@table @t

\JP @item $B;2>H(B

\EG @item References

@fref{modfctr},

@fref{dp_gr_main dp_gr_mod_main dp_gr_f_main},

\JP @fref{$B9`=g=x$N@_Dj(B}.

\EG @fref{Setting term orderings}.

@end table

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