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ArrExponents

exponents of a free arrangement of hyperplanes

Syntax
ArrExponents(Q: RINGELEM): LIST

Description
This function returns the list of exponents of a free arrangement of hyperplanes from its defining equation Q.

Example
/**/ use QQ[x,y];	
/**/ A := [x, x-y, y]; -- free
/**/ Q_A := product(A);	
/**/ ArrExponents(Q_A);
[1,  2]
	
/**/ use QQ[x,y,z];    
/**/ A := [x, x+z, y, 2*y-3*z]; -- not free
/**/ ArrExponents(product(A));
--> ERROR: The input must define a free divisor
...

See Also