## Bug #1081

### ideal() * RingElem gives error

Status:

Closed

Priority:

Normal

Assignee:

Category:

Buggy Maths

Target version:

**Description**

ideal() * RingElem

gives error

### History

#### #1 Updated by Anna Maria Bigatti about 1 year ago

fixed it: now testing

#### #2 Updated by Anna Maria Bigatti about 1 year ago

**Status**changed from*New*to*Feedback***% Done**changed from*0*to*90*

added tests in anna.cocoa5

#### #3 Updated by John Abbott 8 months ago

Should we allow ideals to be multiplied by integers or rational numbers?

I := ideal(x); 2*I; --> ERR not defd I*2; --> ERR not defd RingElem(R,2)*I; --> works I*RingElem(R,2); --> works

Also note the difference below:

I*RingElem(R,2); --> loses factor of 2 I*(2*y); --> keeps factor of 2

Is this behaviour what we want?

#### #4 Updated by Anna Maria Bigatti 8 months ago

John Abbott wrote:

Should we allow ideals to be multiplied by integers or rational numbers?

I vote "no"

**JAA responds** OK, let's try without; if later we need it, we can easily add it.

Also note the difference below:

[...]

Is this behaviour what we want?

This is the only case where it matters, and it works:

/**/ ideal(ZZ, [3]); ideal(3) /**/ It * RingElem(ZZ,2);; ideal(6)

I think it's good enough as it is.

#### #5 Updated by John Abbott 8 months ago

**Status**changed from*Feedback*to*Closed***% Done**changed from*90*to*100*