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7.7.10.0. AltVarStart
Procedure from library nctools.lib (see nctools_lib).

Usage:
AltVarStart();

Return:
int

Purpose:
returns the number of the first alternating variable of basering

Note:
basering should be a super-commutative algebra with at most one block of anti-commutative variables
For commutative rings, nvars(basering)+1 will be returned.

Example:
 
LIB "nctools.lib";
ring R = 0,(x(1..4)),dp; // global!
def ER = superCommutative(2); // (b = 2, e = N)
setring ER; ER;
==> //   characteristic : 0
==> //   number of vars : 4
==> //        block   1 : ordering dp
==> //                  : names    x(1) x(2) x(3) x(4)
==> //        block   2 : ordering C
==> //   noncommutative relations:
==> //    x(3)x(2)=-x(2)*x(3)
==> //    x(4)x(2)=-x(2)*x(4)
==> //    x(4)x(3)=-x(3)*x(4)
==> // quotient ring from ideal
==> _[1]=x(4)^2
==> _[2]=x(3)^2
==> _[3]=x(2)^2
"Alternating variables: [", AltVarStart(), ",", AltVarEnd(), "].";
==> Alternating variables: [ 2 , 4 ].


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