User Matt N. - Mathematics Stack Exchange

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	15,230 reputation	bio	website		visits	member for	2 years, 4 months
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29

50

votes

16

answers

2

kviews

Your favourite application of the Baire category theorem

apr 17 at 14:18 Seirios 8,802

6

17

votes

3

answers

575

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When do weak and original topology coincide?

general-topology functional-analysis topological-vector-spaces

may 10 '12 at 15:56 Martin Sleziak 20.3k

2

13

votes

2

answers

379

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Question about the Riesz representation theorem(s)

functional-analysis measure-theory

aug 16 at 18:19 tomasz 6,964

3

11

votes

3

answers

729

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Proof of $(\mathbb{Z}/m\mathbb{Z}) \otimes_\mathbb{Z} (\mathbb{Z} / n \mathbb{Z}) \cong \mathbb{Z}/ \gcd(m,n)\mathbb{Z}$

commutative-algebra modules

aug 5 at 16:05 Matt N. 15.2k

11

votes

3

answers

235

views

What are rational integer coefficients?

commutative-algebra terminology

jul 18 at 15:20 KennyTM 3,265

1

10

votes

1

answer

141

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Allowing addition of ordinals in forcing

set-theory forcing

jan 27 at 16:30 Asaf Karagila 90.5k

1

10

votes

3

answers

506

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A question regarding the definition of Galois group

abstract-algebra group-theory field-theory galois-theory

nov 17 at 19:10 Matt N. 15.2k

2

10

votes

1

answer

233

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$(n^2 \alpha \bmod 1)$ is equidistributed in $\mathbb{T}^2$ if $\alpha \in \mathbb{R} \setminus \mathbb{Q}$

homework functional-analysis ergodic-theory equidistribution

nov 11 at 20:05 froggie 4,920

1

10

votes

1

answer

274

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Question about whether axiom of choice is needed in this proof

commutative-algebra set-theory axiom-of-choice

oct 16 at 18:38 Matt N. 15.2k

4

10

votes

2

answers

734

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Chicken-Egg problem with Fubini’s theorem

real-analysis measure-theory

jul 17 at 19:38 Matt N. 15.2k

2

9

votes

8

answers

496

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Neatest proof that set of finite subsets is countable?

elementary-set-theory set-theory

apr 14 at 22:33 N. S. 27.3k

1

9

votes

1

answer

81

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Proof of a basic $AC_\omega$ equivalence

reference-request set-theory axiom-of-choice

apr 6 at 19:55 Matt N. 15.2k

2

9

votes

5

answers

280

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$\varphi$ in $\operatorname{Hom}{(S^1, S^1)}$ are of the form $z^n$

abstract-algebra group-theory algebraic-topology representation-theory

nov 17 at 19:09 Matt N. 15.2k

2

9

votes

3

answers

781

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Question about basis and finite dimensional vector space

linear-algebra vector-spaces definition

jul 21 at 13:41 Matt N. 15.2k

9

votes

2

answers

174

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If $V \times W$ with the product norm is complete, must $V$ and $W$ be complete?

vector-spaces banach-spaces examples-counterexamples normed-spaces

jul 10 at 15:20 Dylan Moreland 13.4k

1

8

votes

2

answers

164

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Why does $\omega$ have the same cardinality in every (transitive) model of ZF?

set-theory cardinals

nov 3 at 23:23 Asaf Karagila 90.5k

7

votes

0

answers

128

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If $d$ is a metric and $f$ a function when is $d \circ f $ a metric? [duplicate]

real-analysis metric-spaces

feb 12 at 20:22 Matt N. 15.2k

1

7

votes

3

answers

188

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Complete first order theory with finite model is categorical

elementary-set-theory model-theory

nov 19 at 16:39 Carl Mummert 25.4k

2

7

votes

2

answers

237

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Seifert matrices and Arf invariant — Cinquefoil knot

algebraic-topology manifolds knot-theory

oct 16 at 20:30 IHaveAStupidQuestion 628

7

votes

1

answer

118

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“Multi-facets” rope puzzle

abstract-algebra group-theory puzzle recreational-mathematics

oct 14 at 7:51 Matt N. 15.2k

2

7

votes

1

answer

196

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Seifert matrices — Figure 8 knot

knot-theory

sep 5 at 10:28 Matt N. 15.2k

1

7

votes

2

answers

202

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Domain of an operator in functional analysis

functional-analysis definition normed-spaces

aug 15 at 15:25 Matt N. 15.2k

2

7

votes

5

answers

272

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Question about proof of $A[X] \otimes_A A[Y] \cong A[X, Y] $

commutative-algebra tensor-products

aug 5 at 16:01 Matt N. 15.2k

5

7

votes

4

answers

3

kviews

Space of bounded continuous functions is complete

functional-analysis banach-spaces

jul 8 at 22:19 BenjaLim 16.7k

3

7

votes

2

answers

1

kviews

Proof: $X^\ast$ separable $\implies X$ separable

homework functional-analysis banach-spaces

mar 29 '12 at 19:32 Matt N. 15.2k

3

7

votes

2

answers

583

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$C_c(X)$ dense in $L_1(X)$

homework measure-theory functional-analysis

jan 4 '12 at 12:09 Matt N. 15.2k

3

7

votes

1

answer

756

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Properties of dual spaces of sequence spaces

homework functional-analysis banach-spaces

nov 20 '11 at 14:36 t.b. 43.1k

1

7

votes

2

answers

575

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Homotopy equivalence iff both spaces are deformation retracts

algebraic-topology

may 5 '11 at 23:02 Leon Lampret 2,625

6

votes

3

answers

101

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Proof of $CFE \implies BPI$

set-theory axiom-of-choice

apr 6 at 11:15 Matt N. 15.2k

6

votes

3

answers

151

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A question about a proof in one of Sierpiński's papers

general-topology axiom-of-choice

mar 12 at 18:27 Dave L. Renfro 6,586

Matt N.

428 Questions