getNonUnit -- retrieve a previously discovered non-unit

Usage:

getNonUnit R
Inputs:
- R, a ring, in which division by a non-unit may have been attempted
Outputs:
- a ring element, the non-unit, if any, or null

Description

If a ring has been declared to be a field, using toField or frac, but a nonzero element is found to not be a unit, this routine will return that element, otherwise null is returned.

i1 : A = ZZ/101[a]/(a^2-1);

i2 : toField A

o2 = A[]

o2 : PolynomialRing

i3 : 1//(a-1)

o3 = 0

o3 : A

i4 : getNonUnit A

Warning: this function does not work yet for divisions attempted in the course of computing a Gröbner basis or resolution.

For the programmer

The object getNonUnit is a function closure.

The source of this document is in Macaulay2Doc/functions/getNonUnit-doc.m2:28:0.

getNonUnit -- retrieve a previously discovered non-unit

Description

See also

For the programmer