User Hui Yu - Mathematics Stack Exchange

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	3,792 reputation	bio	website		visits	member for	1 year, 6 months
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More than 99% of groups of order less than 2000 are of order 1024?

apr 15 at 20:46 Alexander Gruber 15.1k

3

15

votes

4

answers

626

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How did the ancients view infinitesimals?

calculus reference-request logic intuition math-history

feb 19 at 15:18 Peter Smith 11.4k

2

14

votes

1

answer

125

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What do characteristic polynomials characterize?

linear-algebra abstract-algebra matrices

feb 19 at 16:08 Marc van Leeuwen 23.7k

4

13

votes

1

answer

277

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How does $\sigma(T)$ change with respect to $T$?

reference-request functional-analysis banach-spaces operator-theory operator-algebras

nov 11 at 13:20 Norbert 19.9k

4

12

votes

2

answers

340

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$(x,y)\to xy$ continuous but $x\to x^{-1}$ not

general-topology group-theory topological-groups

jan 2 '12 at 14:04 Abcd J 269

2

10

votes

1

answer

81

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Other Euler characteristics?

linear-algebra abstract-algebra field-theory category-theory examples-counterexamples

feb 6 at 23:58 Martin Brandenburg 22.4k

3

8

votes

2

answers

82

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$R$ with an upper bound for degrees of irreducibles in $R[x]$

abstract-algebra polynomials ring-theory prime-numbers modules

feb 5 at 7:36 JSchlather 9,735

3

8

votes

1

answer

167

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Importance of Toeplitz operators?

reference-request operator-theory spectral-theory

jan 30 at 0:17 Haskell Curry 11.1k

2

8

votes

1

answer

140

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Do we have Maximal Abelian Algebras (MAAs)?

measure-theory operator-theory examples-counterexamples operator-algebras von-neumann-algebras

jan 19 at 17:05 Paul 289

2

8

votes

2

answers

147

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What was Klein working on when he “replaces his Riemann surface by a metallic surface”?

reference-request soft-question intuition math-history examples-counterexamples

dec 21 at 15:29 Matt E 57.6k

8

votes

1

answer

89

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If $X^$ is isomorphic to $Y^$, what do we know about $X$ and $Y$?

functional-analysis banach-spaces

nov 21 at 17:08 Martin Argerami 16.8k

1

8

votes

2

answers

552

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If $A$ and $B$ are compact, then so is $A+B$.

homework functional-analysis topological-vector-spaces compactness

oct 14 at 5:16 juniven 601

2

8

votes

1

answer

213

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Every multiplicative linear functional on $\ell^{\infty}$ is the limit along an ultrafilter.

real-analysis analysis functional-analysis banach-spaces filters

jul 29 at 9:02 Martin Sleziak 20.3k

3

8

votes

1

answer

115

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Lindelöf'ize a space?

general-topology

mar 14 '12 at 19:54 t.b. 43.1k

3

8

votes

1

answer

310

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What is the use of Spectral Theorem?

hilbert-spaces operator-theory spectral-theory operator-algebras

jan 9 '12 at 16:31 Community♦ 1

2

7

votes

2

answers

103

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Algebraic geometry in representation theory?

abstract-algebra algebraic-geometry representation-theory intuition big-list

may 4 at 17:16 Alistair Savage 1,379

1

7

votes

2

answers

146

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What good are free groups?

abstract-algebra group-theory category-theory free-groups

mar 28 at 17:41 Alexander Gruber 15.1k

1

7

votes

1

answer

77

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Can we really understand $R$ by studying $R$-modules? [duplicate]

abstract-algebra reference-request commutative-algebra category-theory modules

mar 28 at 15:22 Community♦ 1

3

7

votes

1

answer

159

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Categorify a proof?

category-theory proof-strategy examples-counterexamples

feb 5 at 19:06 Community♦ 1

1

7

votes

1

answer

233

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Groups with only one element of order 2

abstract-algebra group-theory proof-strategy

nov 15 at 12:55 espen180 1,396

7

votes

1

answer

405

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Sex, Crime and Functional Analysis?

functional-analysis reference-request soft-question

sep 19 at 5:47 Hui Yu 3,792

7

votes

3

answers

473

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The pronuncation of “Tychonoff” and “Alaoglu”

soft-question math-history

aug 23 at 13:35 Arkamis 7,957

1

7

votes

1

answer

198

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Every hilbert space operator is a combination of projections

functional-analysis hilbert-spaces operator-theory

jul 1 at 7:45 Jonas Meyer 35k

7

votes

1

answer

187

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How to present a paper?

soft-question

may 27 '12 at 17:22 Neal 6,432

7

votes

0

answers

226

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Motivation for abstract harmonic analysis

banach-spaces harmonic-analysis operator-algebras

dec 26 '11 at 2:31 Hui Yu 3,792

6

votes

1

answer

44

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Given $G$, when can we find a division ring $R$ with $R^*=G$?

abstract-algebra group-theory ring-theory field-theory

may 15 at 15:11 rschwieb 20.7k

1

6

votes

2

answers

104

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Why are (representations of ) quivers such a big deal?

linear-algebra reference-request category-theory representation-theory

apr 26 at 19:24 Aaron 757

2

6

votes

1

answer

218

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Age of Stochasticity?

probability soft-question stochastic-processes intuition philosophy

apr 18 at 16:37 Gustavo Bandeira 2,382

1

6

votes

1

answer

74

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Changing research topics completely when entering graduate school?

soft-question career-development

apr 7 at 20:37 Community♦ 1

2

6

votes

2

answers

120

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Stone-Čech via $C_b(X)\cong C(\beta X)$

general-topology functional-analysis banach-algebras

dec 18 at 22:11 Qiaochu Yuan 117k

Hui Yu

144 Questions