Question

Are there maps $(0,\infty)\to (0,\infty)$ that are ${\mathbb Q}$-affine but not ${\mathbb R}$-affine?

score 84 · Answer 1 · 2020-10-04 11:24:06

84

Views

Are there maps $(0,\infty)\to (0,\infty)$ that are ${\mathbb Q}$-affine but not ${\mathbb R}$-affine?

Published on 04 Oct 2020 - 11:24

score 62 · Answer 2 · 2020-10-04 23:56:30

62

Views

Could this be a choice function for powersets of $\mathbb{R}$?

Published on 04 Oct 2020 - 23:56

score 85 · Answer 3 · 2026-03-25 23:38:37

85

Views

Failure of Hahn-Banach in symmetric models

Published on 25 Mar 2026 - 23:38

score 70 · Answer 4 · 2026-02-25 23:14:18

70

Views

Construct a sequence of choice functions such that their defined well-orders are not isomorphic to each other

Published on 25 Feb 2026 - 23:14

score 28 · Answer 5 · 2020-10-11 19:03:03

28

Views

Creating an equinumerous disjoint set without axiom of choice

Published on 11 Oct 2020 - 19:03

score 139 · Answer 6 · 2026-04-06 03:40:19

139

Views

How does $\mathsf{ZF}$ prove the countability of ordinals coming out of functions such as the ordinal collapse function?

Published on 06 Apr 2026 - 3:40

score 46 · Answer 7 · 2020-10-16 15:13:30

46

Views

Question regarding a step in a proof of Zorn's Lemma

Published on 16 Oct 2020 - 15:13

score 98 · Answer 8 · 2020-10-18 09:19:55

98

Views

$\aleph_0$ like cardinalities

Published on 18 Oct 2020 - 9:19

score 281 · Answer 9 · 2020-10-20 13:25:39

281

Views

Confusion in Proof of "Zorn's Lemma $\implies$ Tukey's Lemma"

Published on 20 Oct 2020 - 13:25

score 111 · Answer 10 · 2026-04-07 11:17:07

111

Views

Recursive definition of set and axiom of choice

Published on 07 Apr 2026 - 11:17

score 267 · Answer 11 · 2020-10-28 20:02:03

267

Views

Are these "finite-ish" sets closed under union?

Published on 28 Oct 2020 - 20:02

score 867 · Answer 12 · 2026-03-25 19:02:42

867

Views

What is the dimension of a vector space without a basis?

Published on 25 Mar 2026 - 19:02

score 51 · Answer 13 · 2026-03-25 22:10:55

51

Views

The Sequence Lemma and the Axiom of Countable Choice

Published on 25 Mar 2026 - 22:10

score 75 · Answer 14 · 2026-03-28 22:29:54

75

Views

Does the existence of solutions of $P(x)\equiv 0\pmod{\mathfrak{m}^n}$ for all $n$ gives a solution of $P(x)=0$?

Published on 28 Mar 2026 - 22:29

score 232 · Answer 15 · 2020-11-03 14:27:50

232

Views

Is there an object such that its unique existence follows from choice axiom, while its existence cannot be proven without choice axiom?

Published on 03 Nov 2020 - 14:27

List Question

Are there maps $(0,\infty)\to (0,\infty)$ that are ${\mathbb Q}$-affine but not ${\mathbb R}$-affine?

Could this be a choice function for powersets of $\mathbb{R}$?

Failure of Hahn-Banach in symmetric models

Construct a sequence of choice functions such that their defined well-orders are not isomorphic to each other

Creating an equinumerous disjoint set without axiom of choice

How does $\mathsf{ZF}$ prove the countability of ordinals coming out of functions such as the ordinal collapse function?

Question regarding a step in a proof of Zorn's Lemma

$\aleph_0$ like cardinalities

Confusion in Proof of "Zorn's Lemma $\implies$ Tukey's Lemma"

Recursive definition of set and axiom of choice

Are these "finite-ish" sets closed under union?

What is the dimension of a vector space without a basis?

The Sequence Lemma and the Axiom of Countable Choice

Does the existence of solutions of $P(x)\equiv 0\pmod{\mathfrak{m}^n}$ for all $n$ gives a solution of $P(x)=0$?

Is there an object such that its unique existence follows from choice axiom, while its existence cannot be proven without choice axiom?

Trending Questions

Popular # Hahtags

Popular Questions