83

Questions

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2

votes

0

answers

75

views

Distinct eigenvalues of the quadratic eigenvalue problem

nonlinear-eigenvalue linear-algebra quadratic-eigenvalue

jan 15 at 15:19 Felix Goldberg 2,385●5●12

2

votes

1

answer

99

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Is Ryser’s conjecture on permanent minimizers still open?

permanent matrix-theory combinatorial-designs linear-algebra convexity

apr 25 at 23:17 Ian Wanless 41●1

2

votes

1

answer

39

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Lower bounds on cardinality of a union of blocks in a design

co.combinatorics combinatorial-designs design-theory

may 1 at 17:16 Felix Goldberg 2,385●5●12

2

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0

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126

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If a graph invariant is NP-Hard, is its “deck ratio” NP-Hard as well?

graph-theory computational-complexity graph-reconstruction

jan 11 at 14:45 Felix Goldberg 2,385●5●12

2

votes

1

answer

190

views

How random are random spanning trees?

graph-theory spanning-tree random-graphs

jan 28 at 1:34 Aaron Meyerowitz 11.6k●1●10●31

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2

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2

answers

208

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Motivation for Frankl’s conjecture?

co.combinatorics set-systems hypergraph

2d ago Russ Woodroofe 691●1●4●6

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0

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34

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Which matrix/operator in a cone has the smallest negative spectral part?

cones convexity matrix-analysis norms eigenvalue

may 4 at 12:36 Felix Goldberg 2,385●5●12

1

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2

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81

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Incidence matrices of generalized quadrangles

co.combinatorics generalized-quadrangle resources incidence-geometry

may 13 at 12:45 John Bamberg 193●6

1

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0

answers

46

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Toroidality testing

graph-theory toroidal-graph algorithms

jan 21 at 17:22 Felix Goldberg 2,385●5●12

1

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5

answers

190

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Pairwise balanced designs with $r=\lambda^{2}$

co.combinatorics combinatorial-designs nt.number-theory

jan 30 at 16:20 Aaron Meyerowitz 11.6k●1●10●31