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7.5.3.0. inCenter
Procedure from librarycentral.lib (see central_lib).
- Usage:
- inCenter(E); E poly/list/ideal
- Return:
- integer, 1 if E is in the center, 0 otherwise
- Purpose:
- check whether the elements of E are central
LIB "central.lib"; ring R=0,(x,y,z),dp; matrix D[3][3]=0; D[1,2]=-z; D[1,3]=2*x; D[2,3]=-2*y; def r = nc_algebra(1,D); setring r; // this is U(sl_2) poly p=4*x*y+z^2-2*z; inCenter(p); ==> 1 poly f=4*x*y; inCenter(f); ==> 0 list l= list( 1, p, p^2, p^3); inCenter(l); ==> 1 ideal I= p, f; inCenter(I); ==> 0 |