User Will Orrick - Mathematics Stack Exchange

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	2,532 reputation	bio	website	willorrick.wordpress.com	visits	member for	2 years, 6 months
412 badges		location			seen	22 hours ago

11

21

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answer

1

kviews

Why isn't the 3 body problem solvable?

mar 18 at 17:27 Jamahl Peavey 39

3

16

votes

2

answers

477

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Does Birkhoff - von Neumann imply any of the fundamental theorems in combinatorics?

combinatorics graph-theory order-theory

mar 26 at 23:55 azimut 5,478

7

14

votes

2

answers

470

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Asymptotics of sum of binomials

analysis asymptotics binomial-coefficients

apr 19 at 22:09 robjohn♦ 59.5k

6

13

votes

1

answer

117

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What is duality?

linear-algebra geometry intuition duality-theorems

apr 19 at 7:42 MvG 2,562

7

13

votes

3

answers

412

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Proving that $\sum_{i=0}^{n}\binom{n}{i}i^{n-i}(n-i)^{i}\le\frac{1}{2}n^n$

inequality binomial-coefficients summation

apr 6 at 1:22 i707107 1,189

4

13

votes

2

answers

388

views

Signed Multinomial Expansion Coefficients?

combinatorics polynomials

mar 26 at 9:09 Will Orrick 2,532

10

12

votes

7

answers

1

kviews

What are some good iPhone/iPod Touch/iPad Apps for mathematicians?

geometry big-list math-software computer-algebra-systems hardware

apr 2 at 18:39 user70659 1

5

11

votes

2

answers

301

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When does “pairwise” strengthen and when does it weaken?

soft-question terminology relations

jan 16 at 22:08 alancalvitti 1,153

4

10

votes

3

answers

225

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Problem about subsets of $\{1, 2,\dots,n\}$

combinatorics elementary-set-theory

mar 20 at 21:18 Sean Eberhard 2,708

5

10

votes

1

answer

172

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Graph theory question

graph-theory

mar 26 at 14:46 Aline Parreau 251

4

8

votes

3

answers

157

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Find a ternary $4\times 39$ matrix satisfying the conditions below

homework combinatorics matrices

may 18 at 0:05 Will Orrick 2,532

4

8

votes

2

answers

693

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Elegant Trigonometric Sums

trigonometry

jul 20 at 11:36 user33862 36

2

7

votes

0

answers

182

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Lucky chance or combinatorial cause?

combinatorics

may 7 '12 at 9:34 Johann Cigler 131

2

7

votes

0

answers

141

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Generating the partners in a multi-dimensional irreducible representation.

representation-theory finite-groups

apr 18 '12 at 16:42 rcollyer 864

1

6

votes

2

answers

241

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Is there an $O(n^2)$ test to determine if an $n \times n$ Boolean matrix $B$ has an inverse?

matrices boolean-algebra

feb 23 '12 at 5:58 Derek O'Connor 365

1

6

votes

0

answers

138

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Is there a Steiner system S(6,9,45)?

combinatorics

mar 22 at 12:57 Joubarc 131

3

6

votes

0

answers

78

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The right way to motivate lattice theory in a combinatorics class

combinatorics lattice-orders

apr 19 at 18:50 Brian M. Scott 154k

2

5

votes

1

answer

113

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Combinatorial puzzle

combinatorics sequences-and-series generating-functions

apr 19 at 14:26 Hans Stricker 2,647

2

5

votes

1

answer

164

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Are Clifford algebras and differential forms equivalent frameworks for differential geometry?

differential-geometry differential-forms clifford-algebras

apr 28 at 21:27 DFlores 41

1

5

votes

1

answer

109

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Proof of Konig's theorem on matchings

graph-theory

may 9 at 5:30 zyx 10.9k

2

5

votes

0

answers

83

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relationship between solution of quintic in terms of $_{4}F_{3}$ hypergeometric function and theta functions

reference-request polynomials special-functions

apr 25 '12 at 13:20 deoxygerbe 1,908

1

4

votes

1

answer

120

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What is the difference between first and second right eigenvectors of a row stochastic matrix and their meaning?

linear-algebra matrices graph-theory eigenvectors algebraic-graph-theory

mar 17 at 16:35 Will Orrick 2,532

2

4

votes

1

answer

155

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Finding a system of sets resembling the projective plane

combinatorics combinatorial-designs

mar 10 at 16:14 Will Orrick 2,532

2

4

votes

0

answers

67

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Probability binary Toeplitz matrix invertible

linear-algebra probability matrices

apr 27 at 16:57 marshall 33

3

4

votes

1

answer

81

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Discreteness of eigenvalues for certain operators - can this approach be made rigorous?

real-analysis functional-analysis reference-request proof-strategy intuition

apr 21 at 8:11 Sharkos 4,350

3

votes

1

answer

82

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Bounding the magnitude of the Fourier Transform of the indicator function of a Voronoi cell

geometry fourier-analysis

apr 27 at 8:12 achille hui 6,292

2

3

votes

2

answers

109

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For a simple XML doc, how to find number of possible arrangements of elements (i.e open and close tags) when given maximum number of tags?

combinatorics computer-science

jan 2 at 17:37 Will Orrick 2,532

2

3

votes

2

answers

321

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Ramanujan 691 congruence

number-theory modular-forms

jun 17 '12 at 4:08 Matt E 57.8k

2

3

votes

1

answer

105

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Existence of a binary symmetric matrix from row sums

combinatorics matrices

apr 26 '12 at 2:37 galath 245

2

3

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2

answers

372

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Classification of simple modules for algebra of upper triangular matrices?

linear-algebra abstract-algebra matrices reference-request modules

apr 22 '12 at 2:30 Qiaochu Yuan 117k

Will Orrick

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