Opened 7 years ago

Closed 7 years ago

#16360 closed defect (fixed)

Conversion of function field elements to pari

Reported by: saraedum Owned by:
Priority: major Milestone: sage-6.3
Component: commutative algebra Keywords: pari, resultant, function field, sd59
Cc: mmarco Merged in:
Authors: Julian Rueth Reviewers: Peter Bruin
Report Upstream: N/A Work issues:
Branch: 14f0fff (Commits) Commit: 14f0fff47bbd333409533f626c3368d4ff37dd66
Dependencies: Stopgaps:

Description (last modified by saraedum)

The resultant does not work for function fields if the variable names are not chosen wisely 

sage: K.<x> = FunctionField(QQ)
sage: R.<y> = K[]
sage: y.resultant(y+x)
PariError: variable must have higher priority in gtopoly

The resultant is wrong over extensions of function fields 

sage: K.<a> = FunctionField(QQ)
sage: R.<b> = K[]
sage: L.<b> = K.extension(b^2-a)
sage: R.<x> = L[]
sage: f=x^2-a
sage: g=x-b
sage: f.resultant(g)
-b + a^2 # should be 0 since f and g have the common root b

Change History (5)

comment:1 Changed 7 years ago by saraedum

  • Branch set to u/saraedum/ticket/16360
  • Created changed from 05/16/14 12:39:35 to 05/16/14 12:39:35
  • Modified changed from 05/16/14 12:39:35 to 05/16/14 12:39:35

comment:2 Changed 7 years ago by saraedum

  • Authors set to Julian Rueth
  • Description modified (diff)
  • Status changed from new to needs_review

comment:3 Changed 7 years ago by saraedum

  • Cc mmarco added
  • Commit set to 14f0fff47bbd333409533f626c3368d4ff37dd66
  • Keywords sd59 added

CCed mmarco since it seems he worked on that before (and is at sd59).

New commits:

​14f0fffFixed resultant for polynomials over function fields.

comment:4 Changed 7 years ago by pbruin

  • Reviewers set to Peter Bruin
  • Status changed from needs_review to positive_review

Looks good and passes tests.

comment:5 Changed 7 years ago by vbraun

  • Branch changed from u/saraedum/ticket/16360 to 14f0fff47bbd333409533f626c3368d4ff37dd66
  • Resolution set to fixed
  • Status changed from positive_review to closed
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