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Strange result https://www.singular.uni-kl.de/forum/viewtopic.php?f=10&t=1344 |
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Author: | Carlos Bahiano [ Thu Aug 11, 2005 5:31 pm ] |
Post subject: | Strange result |
Dear singular team. A friend had asked to me to eliminate the variables x and y from the ideal k below. There is something wrong with Singular but I am not able to tell what it is. Look what i got, that is very strange because the same commands were used very well with others ideals. > ring I = 0,(x,y,u,v,w),dp; > I; // characteristic : 0 // number of vars : 5 // block 1 : ordering dp // : names x y u v w // block 2 : ordering C > option(prot); Ø ideal j = u-xy,v-x4-y5,w+4x4-5y5; > ideal k = u-x*y,v-x^4-y^5-x*y^2-x^3*y,w+4*x^4-5*y^5-x*y^2+2*x^3*y; > eliminate (k,xy); [63:3]2(2)s5ss6ss7(3)s-8-s9-ss10(5)s(6)-s(7)s(9)-s11(11)s(13)s(15)s(14)--s12 -s(15)s(18)s(21)---s---13-s(17)s(20)s(23)s(26)------s(23)--14-s(24)s(28)s(29 )sss(30)ss(32)s15s(35)s(36)-s(37)ss(39)s(42)s(45)s(47)s(50)s(52)s(55)s(58)s( 54)s(49)s(47)----s(45)s(48)------16-s(44)s(42)s(40)ss(42)---------------17-s (29)s(32)s(35)s(37)s----------------18-s(23)s(26)s(28)-s(31)--s-----------19 -s(22)s(25)s-------------20-s(14)s(17)s(20)--------21-s(13)s(16)s(19)----s22 (17)ss(20)--------23-s(14)ss(16)s(18)-s(20)--24-ss(17)---s----25-s(12)s(15)s (18)s(21)-s(23)--26-s(20)s(23)s(26)s(27)---s-s(26)s(28)Singular : signal 11 (v: 2003/2002030115): Segment fault/Bus error occurred (r:1035481123) please inform the authors trying to restart... What do you think ? If i use the following the computation just carry on without errors but the answer is not what i expected. ring r =(0,x,y),(z,u,v,w),dp; // ** redefining r ** > r; // characteristic : 0 // 2 parameter : x y // minpoly : 0 // number of vars : 4 // block 1 : ordering dp // : names z u v w // block 2 : ordering C > ideal I = u-x*y,v-x^4-y^5-x*y^2-x^3*y,w+4*x^4-5*y^5-x*y^2+2*x^3*y; > help elim; > eliminate(I,xy); _[1]=w+(4x4+2x3y-xy2-5y5) _[2]=v+(-x4-x3y-xy2-y5) _[3]=u+(-xy) > option(prot); > eliminate(I,xy); [255:3]1(2)sss product criterion:3 chain criterion:0 _[1]=w+(4x4+2x3y-xy2-5y5) _[2]=v+(-x4-x3y-xy2-y5) _[3]=u+(-xy) What is happening? best wishes. Carlos Bahiano. email: bahiano@ufba.br Posted in old Singular Forum on: 2002-12-02 19:11:33+01 |
Author: | Hans Schönemann [ Wed Sep 21, 2005 8:34 pm ] |
Post subject: | |
> > ring I = 0,(x,y,u,v,w),dp; > > ideal k = u-x*y,v-x^4-y^5-x*y^2-x^3*y,w+4*x^4-5*y^5-x*y^2+2*x^3*y; > > > eliminate (k,xy); ... > Segment fault/Bus error occurred (r:1035481123) > please inform the authors > trying to restart... You are probably out of memory in this case. It is better to define the ring as ring I=0,(x,y,u,v,w),(dp(2),dp); ideal k=... ideal kk=groebner(k); and the the result are all polynomial of kk which do not contain x and y. -------------------------------------------------------- > > If i use the following the computation just carry on without errors but the answer is not what i expected. > ring r =(0,x,y),(z,u,v,w),dp; ... > > eliminate(I,xy); You cannot elimate paramters, only variables. email: hannes@mathematik.uni-kl.de Posted in old Singular Forum on: 2003-04-16 11:13:15+02 |
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