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7.10.4.7 isOrderingShiftInvariant
Procedure from libraryfreegb.lib (see freegb_lib).
- Usage:
- isOrderingShiftInvariant(b); b an integer interpreted as a boolean
- Return:
- int
- Note:
- Tests whether the ordering of the current ring is shift invariant, which is the case, when LM(p) > LM(p') for all p and p' where p' is p shifted by any number of places.
If withHoles != 0 even Letterplace polynomials with holes (eg. x(1)*y(4)) are considered.
- Assume:
- - basering is a Letterplace ring.
LIB "freegb.lib"; ring r = 0,(x,y,z),dp; def R = freeAlgebra(r, 5); setring R; isOrderingShiftInvariant(0);// should be 1 ==> 1 ring r2 = 0,(x,y,z),dp; def R2 = freeAlgebra(r2, 5); list RL = ringlist(R2); RL[3][1][1] = "wp"; intvec weights = 1,1,1,1,1,1,1,2,3,1,1,1,1,1,1; RL[3][1][2] = weights; attrib(RL,"isLetterplaceRing",3); attrib(RL,"maxExp",1); def Rw = setLetterplaceAttributes(ring(RL),5,3); setring Rw; /* printlevel = voice + 1; */ isOrderingShiftInvariant(0); ==> 0 isOrderingShiftInvariant(1); ==> 0 |