Matt N.

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Fundamenta Mathematicae.

Biblioteka Wirtualna Matematyki.

	15,230 reputation	bio	website		visits	member for	2 years, 4 months
32270 badges		location			seen	9 hours ago

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428 Questions

views newest activity votes

votes

answers

215

views

A question about a proof of a weak form of Hilbert's Nullstellensatz

commutative-algebra field-theory

jul 19 at 20:25 Rankeya 4,224

votes

answer

111

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Possibly false proof in AM

commutative-algebra

jul 18 at 11:03 Georges Elencwajg 44.8k

votes

answers

201

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Simple application of Stone-Weierstrass

functional-analysis normed-spaces

jul 13 at 22:01 Sam 6,944

votes

answers

132

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What things can be defined in terms of universal properties?

soft-question category-theory

jun 29 at 16:37 Qiaochu Yuan 117k

votes

answers

134

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Example of an application of a theorem about ideals in rings of fractions in Atiyah-MacDonald

commutative-algebra

jun 15 '12 at 21:38 Matt N. 15.2k

votes

answer

165

views

$C \otimes A \cong C \otimes B$ does not imply $A \cong B$

commutative-algebra modules tensor-products

jun 13 '12 at 19:45 Miha Habič 2,121

votes

answer

160

views

Equivalent definition of exactness of functor?

category-theory homological-algebra

jun 13 '12 at 15:02 rschwieb 20.8k

votes

answer

235

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There exists a unique isomorphism $M \otimes N \to N \otimes M$

commutative-algebra tensor-products

jun 12 '12 at 20:36 Arturo Magidin 158k

votes

answers

265

views

Understanding adjoint functors

category-theory adjoint

jun 12 '12 at 6:43 Giuseppe 2,664

votes

answer

180

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Natural transformation

category-theory

jun 10 '12 at 10:13 anon 39.8k

votes

answer

149

views

Universal property of initial topology

general-topology category-theory

apr 29 '12 at 12:26 Martin Wanvik 1,944

votes

answer

142

views

Formal proof involving $\varphi( v_k / v_l )$

logic proof-theory

feb 13 '12 at 6:59 Matt N. 15.2k

votes

answer

153

views

Question about Boolean algebra and ultrafilters

set-theory boolean-algebra lattice-orders

jan 31 '12 at 16:54 André Nicolas 161k

votes

answers

537

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Limit involving floor function

real-analysis limit

jan 24 '12 at 15:43 Michael Hardy 48k

votes

answer

156

views

Proof of $f \in C_C(X)$ where $X$ is a metric space implies $f$ is uniformly continuous

real-analysis

jan 2 '12 at 16:04 Matt N. 15.2k

votes

answer

140

views

Canonical $\mathbb{P}$-name

set-theory forcing

nov 27 '11 at 22:50 Asaf Karagila 90.8k

votes

answers

359

views

A question about the nilradical

abstract-algebra ring-theory

oct 6 '11 at 22:54 Zev Chonoles 53.5k

votes

answers

152

views

Inf sup of an expression not involving sequences

real-analysis

oct 1 '11 at 10:47 Matt N. 15.2k

votes

answer

304

views

$H_1(\mathbb{R}, \mathbb{Q})$ is free abelian

algebraic-topology

sep 6 '11 at 18:11 Mariano Suárez-Alvarez♦ 53.2k

votes

answers

270

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Typo in Hatcher? $\mathbb{R}^n - \{x \} \cong S^{n-1} \times \mathbb{R}$?

analysis algebraic-topology

sep 1 '11 at 20:10 t.b. 43.1k

votes

answers

435

views

Reduced homology

algebraic-topology

aug 8 '11 at 3:54 Sean Tilson 2,443

votes

answers

210

views

Closure of $\{ (x_n) | x_n = 0 $ for almost all $n \}$

general-topology

apr 6 '11 at 0:04 JSchlather 9,735

votes

answers

476

views

A question regarding normal field extensions and Galois groups

abstract-algebra field-theory galois-theory

feb 17 '11 at 21:54 Arturo Magidin 158k

votes

answers

322

views

Proof that $\frac{S_n}{n}$ converges almost surely to $\mu$

probability

feb 11 '11 at 17:26 Byron Schmuland 15.4k

votes

answers

416

views

A question about regularity of Borel measures

measure-theory

may 15 at 17:50 savick01 1,190

votes

answer

views

Dissecting a proof of the $\Delta$-system lemma (part II)

set-theory axiom-of-choice

apr 30 at 13:42 Matt N. 15.2k

votes

answers

views

Cardinal characteristics — generalisation?

reference-request cardinals

apr 17 at 7:54 Matt N. 15.2k

votes

answer

views

Exercise in Just/Weese (amoeba forcing) (1/2)

set-theory forcing

apr 9 at 8:42 Arthur Fischer♦ 21.3k

votes

answers

106

views

Question about passage in Halbeisen's book

set-theory model-theory forcing

apr 5 at 17:52 Martin Sleziak 20.3k

votes

answers

138

views

Characterization of ideals in rings of fractions

commutative-algebra ring-theory

feb 7 at 20:09 Robert 785