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D.14.1.15 arrCoordNormalize

Procedure from library arr.lib (see arr_lib).

Usage:
arrCoordChange(A, v);

Return:
[arr]: Arrangement after a coordinate change that transforms the arrangement such that after a transformation x -> Tx + c we have the arrangement has the matrix representation [AT^-1|b+AT^-1c] such that [AT^-1]_v = I and [b+AT^-1c]_v = 0;

Note:
algorithm performs a base change if H_k is homogeneous (i.e. has no) constant term and an affine transformation otherwise
Ax+b = 0, Transformation x = Ty+c: AT^-1y + AT^-1c + b = 0 Now we want to have (AT^-1)_v = I and (AT^-1c +b)_v = AT^-1_v*c + b_v = 0

Example:
 
LIB "arr.lib";
ring r = 0,(x,y,z),lp;
arr A = ideal(x,y,z,x+z+4);
intvec v = 1,2,4;
arrCoordNormalize(A,v);
==> _[1]=x
==> _[2]=y
==> _[3]=-x+z-4
==> _[4]=z
==> 
See also: arrCoordChange; arrCoordNormalize.


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