57

Questions

votes newest views recent

8

24

votes

3

answers

2k

views

Are there more Nullstellensätze?

ac.commutative-algebra ag.algebraic-geometry

aug 2 11 at 18:18 Emil Jeřábek 10.7k●1●24●41

15

22

votes

7

answers

1k

views

When are there enough projective sheaves on a space X?

ag.algebraic-geometry sheaf-theory homological-algebra gn.general-topology

nov 25 09 at 19:04 Pete L. Clark 39.6k●3●102●225

7

21

votes

5

answers

1k

views

Explicit elements of $K((x))((y)) \setminus K((x,y))$

ac.commutative-algebra fields examples

aug 2 10 at 7:14 Pietro Majer 19.7k●1●24●69

4

18

votes

2

answers

507

views

How much choice is needed to show that formally real fields can be ordered?

fields set-theory lo.logic order-theory axiom-of-choice

mar 1 10 at 0:13 Charles Stewart 1,669●8●15

3

17

votes

3

answers

704

views

Do there exist non-PIDs in which every countably generated ideal is principal?

ac.commutative-algebra set-theory

dec 7 09 at 18:32 Joel David Hamkins 75.3k●7●187●343

8

17

votes

3

answers

2k

views

Subgroups of free abelian groups are free: a topological proof?

at.algebraic-topology gr.group-theory

nov 17 09 at 3:39 Andrew S 1

4

17

votes

3

answers

1k

views

Must a ring which admits a Euclidean quadratic form be Euclidean?

nt.number-theory quadratic-forms euclidean-domain

sep 28 10 at 13:24 Franz Lemmermeyer 17.2k●1●38●101

12

16

votes

3

answers

2k

views

An unfamiliar (to me) form of Hensel’s Lemma

fields valuation-theory reference-request p-adic-analysis

feb 20 10 at 1:56 Wanderer 2,977●12●28

12

15

votes

2

answers

2k

views

A finitely generated, locally free module over a domain which is not projective?

ac.commutative-algebra examples projective-module

feb 8 10 at 7:31 Pete L. Clark 39.6k●3●102●225

5

15

votes

6

answers

928

views

Nonfree projective module over a regular UFD?

ac.commutative-algebra projective-module examples

feb 15 at 11:44 manoj 23●4