Error coercing multivariate polynomial rings with one variable into composite integer rings

[ncalexan]

This works:

sage: PolynomialRing(ZZ, 2, 'x').gen() * Mod(1, 9)
x0
sage: PolynomialRing(ZZ, 2, 'x').gen() * Mod(1, 3)
x0

This doesn't:

sage: PolynomialRing(ZZ, 1, 'x').gen() * Mod(1, 3)
x
sage: PolynomialRing(ZZ, 1, 'x').gen() * Mod(1, 9)
---------------------------------------------------------------------------
<type 'exceptions.TypeError'>             Traceback (most recent call last)

/Users/ncalexan/<ipython console> in <module>()

/Users/ncalexan/element.pyx in sage.structure.element.RingElement.__mul__()

/Users/ncalexan/coerce.pyx in sage.structure.coerce.CoercionModel_cache_maps.bin_op_c()

<type 'exceptions.TypeError'>: unsupported operand parent(s) for '*': 'Multivariate Polynomial Ring in x over Integer Ring' and 'Ring of integers modulo 9'

CC: @robertwb

Component: commutative algebra

Keywords: coercion coerce multivariate univariate composite

Issue created by migration from https://trac.sagemath.org/ticket/1245

[sagetrac-mabshoff]

comment:3

This is still a problem with Sage 2.10.

Cheers,

Michael

[sagetrac-mabshoff]

comment:5

Still an issue with Sage 2.10.2.alpha0.

Cheers,

Michael

[malb]

comment:6

I'm stuck with this bug, I don't know where to look. Robert, can you take a look?

[mwhansen]

comment:7

This has been fixed in at least Sage 3.1.4

sage: sage: PolynomialRing(ZZ, 1, 'x').gen() * Mod(1, 3)
x
sage: sage: PolynomialRing(ZZ, 1, 'x').gen() * Mod(1, 9)
x
sage: _.parent()
Univariate Polynomial Ring in x over Ring of integers modulo 9