[sage-devel] Re: Finite fields coercion bug

Hello, Kwankyu Lee wrote: > On Thursday, October 13, 2016 at 9:59:50 PM UTC+2, David Roe wrote: > > In order to create finite fields with arbitrary variable names that fit > into a lattice of fields, one possibility would be able to give an > algebraic closure explicitly as an argument to

Re: [sage-devel] Re: Finite fields coercion bug

On Thursday, October 13, 2016 at 9:59:50 PM UTC+2, David Roe wrote: > > > In order to create finite fields with arbitrary variable names that fit > into a lattice of fields, one possibility would be able to give an > algebraic closure explicitly as an argument to GF. Is that what you're >

Re: [sage-devel] Re: Finite fields coercion bug

On Thursday, October 13, 2016 at 12:16:36 PM UTC-7, John Cremona wrote: > > Kwankyu's point is also a good one. It really is not acceptable (from > a user's point of view) to ask if there any coercions, be told there > are none, and then be prevented from defining one! > It's a necessity for

Re: [sage-devel] Re: Finite fields coercion bug

On Thu, Oct 13, 2016 at 5:09 PM, Kwankyu Lee wrote: > Hi David, > > First, thank you for technical explanations. They are compelling. > > On Thursday, October 13, 2016 at 9:59:50 PM UTC+2, David Roe wrote: >> >> >> In order to create finite fields with arbitrary variable

Re: [sage-devel] Re: Finite fields coercion bug

Hi David, First, thank you for technical explanations. They are compelling. On Thursday, October 13, 2016 at 9:59:50 PM UTC+2, David Roe wrote: > > > In order to create finite fields with arbitrary variable names that fit > into a lattice of fields, one possibility would be able to give an >

Re: [sage-devel] Re: Finite fields coercion bug

On Thu, Oct 13, 2016 at 3:16 PM, John Cremona wrote: > Thanks Peter for the explanation. Nevertheless, I'm not sure that the > normal user could have guess that one only gets the clever stuff > (compatible embeddings into the algebraci closure. The docstring GF? > does

Re: [sage-devel] Re: Finite fields coercion bug

Thanks Peter for the explanation. Nevertheless, I'm not sure that the normal user could have guess that one only gets the clever stuff (compatible embeddings into the algebraci closure. The docstring GF? does imply this but again does not make a big thing of it. I think a better design (just of

[sage-devel] Re: Finite fields coercion bug

Hi, On Thursday, October 13, 2016 at 7:14:27 PM UTC+2, Peter Bruin wrote: > > Even though there is no coercion map in this situation, simply trying to > discover a coercion "taints" the target parent by registering the fact > that there is no coercion. Then should we consider this behavior as

[sage-devel] Re: Finite fields coercion bug

Hello John, > I think this is a bug. In one Sage session: > > sage: F4 = GF(4) > sage: F16 = GF(16) > sage: F4.gen() in F16 > True > sage: F16.has_coerce_map_from(F4) > True > > -- all is well. But in a new session: > > sage: F4 = GF(4, names='a') > sage: F16 = GF(16, names='b') > sage: