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GB.GetNthSyzShifts

shifts of the Nth syzygy module computed so far
Syntax 

$gb.GetNthSyzShifts(M:IDEAL or MODULE, N:INT):TAGGED("shifts")

Description
This function, if used after executing Res(M), returns the shifts for the Nth syzygy module for M. Within the Interactive Groebner Framework, in which resolutions may be computed one step at a time, the function returns shifts of the part of the Nth syzygy module computed so far.

Example 
  Use R ::= QQ[t,x,y,z];
  I := Ideal(x^2-yt,xy-zt,xy);
  $gb.Start_Res(I);
  $gb.Steps(I,6);
  $gb.GetNthSyzShifts(I,2);
Shifts([x^2yz])
-------------------------------
  $gb.Complete(I);
  $gb.GetNthSyzShifts(I,2);
Shifts([x^2yz, txyz, tx^2z, x^3y])
-------------------------------
  J := Ideal(t,x)^3;
  Res(J);
0 --> R^3(-4) --> R^4(-3)
-------------------------------
  $gb.GetNthSyzShifts(J,1);
Shifts([x^3, tx^2, t^2x, t^3])
-------------------------------
  $gb.GetNthSyzShifts(J,2);
Shifts([tx^3, t^2x^2, t^3x])
-------------------------------
  SS := It;
  SS[1];
tx^3
-------------------------------


See Also