Bug #132
BringIn should allow reduction modulo p
Description
Currently BringIn does not allow one to move from char 0 to char non-zero.
Use QQ[x]; f := x^2+1; Use ZZ/(5)[x]; BringIn(f); --> gives error
Moreover the error message is misleading.
Related issues
History
#1
Updated by Anna Maria Bigatti about 11 years ago
Updated by - Category set to CoCoA-4 function to be added
#2
Updated by John Abbott about 10 years ago
Updated by Even worse: BringIn fails to construct the hom from ZZ/(11)[x,y,z] to ZZ/(11)[x,y,z],Lex
This is embarassing!
Ahhhh! Perhaps the problem was that I created ZZ/(11) twice, and currently they are not regarded as identical.
#3
Updated by John Abbott about 10 years ago
- Status changed from New to In Progress
The example given in the C5 online manual fails (because it uses reduction mod p).
#4
Updated by Anna Maria Bigatti about 10 years ago
- Target version set to CoCoA-5.1.0 Easter14
#5
Updated by John Abbott about 10 years ago
- Target version changed from CoCoA-5.1.0 Easter14 to CoCoA-5.1.1 Seoul14
#6
Updated by Anna Maria Bigatti almost 10 years ago
- Assignee set to Anna Maria Bigatti
- % Done changed from 0 to 50
now works in some cases, e.g. the one in the description ;-)
More precisely it works if the coefficient ring (of the object to move) is a polynomial ring with coefficients in ZZ or QQ.
A bit of a workaround, but that's what BringIn is by its very own nature.
In general it is not guaranteed to work on more complicated ring structures, but in that case I would expect such a user would define a proper RINGHOM.
#7
Updated by John Abbott over 9 years ago
- Status changed from In Progress to Closed
- % Done changed from 50 to 100
Closing even though it only partly resolves the problems with BringIn. I'll create a new, more precise issue.