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7.5.3.0. PBW_maxDeg
Procedure from library central.lib (see central_lib).

Usage:
PBW_maxDeg(MaxDeg); MaxDeg int

Purpose:
Compute PBW elements up to a given maximal degree.

Return:
ideal consisting of found elements.

Note:
unit is omitted. Weights are ignored!

Example:
 
LIB "central.lib";
ring AA = 0,(e,f,h),dp;
matrix D[3][3]=0;
D[1,2]=-h;  D[1,3]=2*e;  D[2,3]=-2*f;
def A = nc_algebra(1,D); // this algebra is U(sl_2)
setring A;
// PBW Basis of A_2 - monomials of degree <= 2, without unit:
PBW_maxDeg( 2 );
==> _[1]=e
==> _[2]=f
==> _[3]=h
==> _[4]=h2
==> _[5]=fh
==> _[6]=f2
==> _[7]=eh
==> _[8]=ef
==> _[9]=e2