Opened 8 years ago
Closed 8 years ago
#661 closed bug (fixed)
incorrect radical entry in a primdecSY() decomposition
Reported by: | Owned by: | somebody | |
---|---|---|---|
Priority: | minor | Milestone: | 4-1-0 and higher |
Component: | dontKnow | Version: | 4-0-1 |
Keywords: | wrong radical primdecSY | Cc: |
Description
example for incorrect radical entry in a primdecSY() decomposition, see second component:
LIB("primdec.lib"); ring rng = (0),(xm,xp,xw,xo,xj,xd,xn,xz),dp; ideal I = -2*xj+19*xo^2, 18*xw*xz+19*xd, -13*xp*xd*xz-16*xo, -2*xj*xn^2+9*xn, 23*xm-8*xj, -17*xm*xn+17*xm*xo, -18*xn*xz+3*xj, 23*xm*xp*xn-30*xw*xn, -6*xm*xw, 23*xj*xd*xz+4*xd*xz, 16*xm*xw+14*xj, -20*xp*xj*xn+27*xz^2, 23*xp*xw+14*xm*xd, 7*xm*xj+29*xo*xd*xn; list L = primdecSY (I); ideal pc2 = L[2][1]; pc2; ideal rpc2 = L[2][2]; // incorrect!! rpc2; radical(L[2][1]); idealsEqual( radical(pc2), rpc2 ); // = 0! /////////////////////////////////////////// // same with groebner(I): L = primdecSY (groebner(I) ); pc2 = L[2][1]; rpc2 = L[2][2]; radical(L[2][1]); idealsEqual( radical(pc2), rpc2 ); //ok!
output
. list L = primdecSY (I); > ideal pc2 = L[2][1]; > pc2; pc2[1]=xn pc2[2]=xd pc2[3]=xj pc2[4]=xo pc2[5]=xw pc2[6]=xm pc2[7]=xz^2 > ideal rpc2 = L[2][2]; > rpc2; rpc2[1]=xz rpc2[2]=xn rpc2[3]=xd rpc2[4]=xj rpc2[5]=xo rpc2[6]=xw rpc2[7]=xp rpc2[8]=xm > radical(L[2][1]); _[1]=xz _[2]=xn _[3]=xd _[4]=xj _[5]=xo _[6]=xw _[7]=xm > . idealsEqual( radical(pc2), rpc2 ); // = 0! 0
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fixed by mlee with 948667d52839562086cf444b0a31a259e43e6b41