Opened 5 years ago

Last modified 5 years ago

#23185 closed defect

A polynomial ring embeds into its fraction field — at Version 7

Reported by: saraedum Owned by:
Priority: minor Milestone: sage-8.0
Component: commutative algebra Keywords: sd86.5, sd87
Cc: Merged in:
Authors: Reviewers:
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: #23167 Stopgaps:

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Description (last modified by saraedum)

Currently, this fails:

sage: R.<x> = QQ[]
sage: K.<x> = FunctionField(QQ)
sage: R.is_subring(K)
NotImplementedError
sage: R.is_subring(R.fraction_field())
NotImplementedError

but it should return True.

The latter could be implemented in the category of ring homomorphisms (to find out whether a map is a coercion, just ask for the coercion between those two rings.)

Change History (7)

comment:1 Changed 5 years ago by saraedum

  • Description modified (diff)

comment:2 Changed 5 years ago by saraedum

  • Description modified (diff)

comment:3 Changed 5 years ago by saraedum

  • Dependencies set to #23167

comment:4 Changed 5 years ago by saraedum

Most likely, we need to patch _coerce_map_from_ of function fields to return an injective homomorphism.

comment:5 Changed 5 years ago by saraedum

  • Keywords sd86.5 added

comment:6 Changed 5 years ago by saraedum

  • Description modified (diff)

comment:7 Changed 5 years ago by saraedum

  • Description modified (diff)
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