Opened 9 years ago

# Multivariate powerseries with symbolic coefficients issues

Reported by: Owned by: vbraun malb major sage-6.4 commutative algebra multivariate power series niles N/A

### Description

Multivariate powerseries over SR seem to work, but coercion does not. For example, the coercion from ZZ to QQ works fine:

```sage: T.<a,b> = PowerSeriesRing(ZZ,2)
sage: f = 1 + a + b + a*b + T.O(5)
sage: 1/2 * f
1/2 + 1/2*a + 1/2*b + 1/2*a*b + O(a, b)^5
```

but the same thing fails with SR:

```sage: exp(2) * f
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)

/home/vbraun/opt/sage-4.8.alpha4/devel/sage-main/sage/schemes/generic/<ipython console> in <module>()

/home/vbraun/opt/sage-4.8.alpha4/local/lib/python2.6/site-packages/sage/structure/element.so in sage.structure.element.RingElement.__mul__ (sage/structure/element.c:12158)()

/home/vbraun/opt/sage-4.8.alpha4/local/lib/python2.6/site-packages/sage/structure/coerce.so in sage.structure.coerce.CoercionModel_cache_maps.bin_op (sage/structure/coerce.c:7467)()

TypeError: unsupported operand parent(s) for '*': 'Symbolic Ring' and 'Multivariate Power Series Ring in a, b over Integer Ring'
```

Also, manually changing the base ring brings out the background polynomial variable:

```sage: f.change_ring(SR)
(Tbg*a*b + a + b)*Tbg + 1 + O(a, b)^5
```

### comment:1 Changed 8 years ago by jdemeyer

• Milestone changed from sage-5.11 to sage-5.12

### comment:2 Changed 7 years ago by vbraun_spam

• Milestone changed from sage-6.1 to sage-6.2

### comment:3 Changed 7 years ago by vbraun_spam

• Milestone changed from sage-6.2 to sage-6.3

### comment:4 Changed 7 years ago by vbraun_spam

• Milestone changed from sage-6.3 to sage-6.4
Note: See TracTickets for help on using tickets.