User user6818

3

13

votes

3

answers

3k

views

What is a “Ramanujan Graph”?

May 31 '15 at 18:27 Community♦ 1

2

11

votes

3

answers

713

views

Are these three different notions of a graph Laplacian?

graph-theory real-analysis sp.spectral-theory spectral-graph-theory laplacian

Dec 2 '14 at 5:31 Richard Zhang 550

9

votes

0

answers

158

views

Is there a ``Ladner's Theorem" for the PH-vs-PSPACE scenario?

polynomials computational-complexity model-theory formal-languages

Mar 4 '15 at 21:43 user6818 1,785

2

8

votes

1

answer

444

views

Are there exactly solvable CFTs?

rt.representation-theory mp.mathematical-physics quantum-field-theory conformal-field-theory virasoro-algebra

Feb 12 '16 at 15:30 Abdelmalek Abdesselam 17.3k

7

8

votes

6

answers

2k

views

What is a branched Riemann surface with cuts?

ag.algebraic-geometry algebraic-curves riemann-surfaces quantum-field-theory string-theory

Jul 10 '13 at 12:14 Andrew D. Hwang 266

7

votes

2

answers

246

views

What methods do we have to understand the spectrum of matrices with restricted entries?

reference-request linear-algebra matrices additive-combinatorics convex-optimization

May 22 '15 at 4:11 Community♦ 1

1

7

votes

2

answers

444

views

Constructing Ramanujan graphs from elliptic curves

ag.algebraic-geometry reference-request algebraic-number-theory spectral-graph-theory expander-graphs

Apr 8 '15 at 17:51 Igor Rivin 92.2k

3

7

votes

1

answer

902

views

When are (Abelian) Cayley graphs also expanders?

gr.group-theory graph-theory computational-complexity spectral-graph-theory expander-graphs

Mar 8 '15 at 12:37 Sebi Cioaba 421

4

6

votes

2

answers

478

views

Do perfect matching(s) have signatures in the graph eigenvalues?

graph-theory sp.spectral-theory spectral-graph-theory algebraic-graph-theory

May 14 '18 at 12:53 Nick Ulyanov 25

1

5

votes

2

answers

521

views

Matching polynomials and Ramanujan graphs

graph-theory sp.spectral-theory spectral-graph-theory matching-theory expander-graphs

Apr 22 '20 at 23:24 bah 1

5

votes

0

answers

205

views

What do we know about isospectral Cayley graphs?

gr.group-theory rt.representation-theory graph-theory lie-groups isospectrality

Oct 27 '16 at 0:32 emiliocba 1,804

1

5

votes

1

answer

119

views

How does one go from convexity to submodularity?

discrete-geometry linear-programming convex-optimization nonlinear-optimization nonlinear-eigenvalue

Sep 8 '16 at 8:42 Undertherainbow 111

4

5

votes

1

answer

520

views

Proof of the general expression for anomaly in a CFT and its partition function

dg.differential-geometry riemannian-geometry quantum-field-theory string-theory conformal-geometry

Aug 28 '13 at 23:11 Rafe Mazzeo 1,944

1

4

votes

1

answer

517

views

About using the character formula for $SO(2n)$

rt.representation-theory lie-groups mp.mathematical-physics lie-algebras physics

Mar 1 at 10:21 Glorfindel 2,260

4

votes

0

answers

526

views

Can one integrate around a branch-cut?

fa.functional-analysis cv.complex-variables complex-geometry real-analysis

Oct 16 '15 at 7:23 user6818 1,785

4

votes

3

answers

395

views

Reference request about the representations of the group $PSL_2(\mathbb{F}_q)$

reference-request rt.representation-theory lie-groups projective-geometry

Apr 19 '15 at 4:34 Amritanshu Prasad 5,174

1

4

votes

0

answers

550

views

Is there a method to simultaneously block-diagonalize a set of group matrices?

fa.functional-analysis rt.representation-theory linear-algebra matrices determinants

Mar 15 '15 at 21:17 user6818 1,785

4

votes

0

answers

472

views

The Bilu-Linial conjecture and Ramanujan graphs

nt.number-theory graph-theory sp.spectral-theory spectral-graph-theory expander-graphs

Jan 11 '15 at 7:38 user6818 1,785

3

votes

1

answer

219

views

Can we count isospectral graphs?

graph-theory fourier-analysis sp.spectral-theory isospectrality

Feb 24 '16 at 13:01 Community♦ 1

3

votes

1

answer

985

views

What are Euler density and Weyl invariants?

dg.differential-geometry riemannian-geometry quantum-field-theory conformal-field-theory conformal-geometry

Jun 4 '15 at 20:25 Community♦ 1

1

3

votes

1

answer

238

views

About the second largest adjacency eigenvalue of Abelian Cayley graphs

gr.group-theory rt.representation-theory graph-theory spectral-graph-theory

Mar 17 '15 at 1:24 user6818 1,785

1

3

votes

0

answers

223

views

About the small set expansion conjecture

fa.functional-analysis graph-theory real-analysis computational-complexity spectral-graph-theory

Mar 9 '15 at 23:24 user6818 1,785

2

3

votes

1

answer

402

views

The Fuchsian monodromy problem

riemann-surfaces quantum-field-theory string-theory fuchsian-groups monodromy

Jun 8 '14 at 11:32 Community♦ 1

2

votes

1

answer

497

views

Some identities with the Riemann-Hurwitz zeta function

algebraic-number-theory analytic-number-theory riemann-zeta-function quantum-field-theory renormalization

Jul 4 '16 at 3:39 Community♦ 1

2

votes

1

answer

823

views

About distinct eigenvalues of a graph

linear-algebra polynomials sp.spectral-theory spectral-graph-theory

Aug 26 '15 at 21:47 Sebi Cioaba 421

3

2

votes

5

answers

2k

views

About adding a negative definite rank-1 matrix to a symmetric matrix

linear-algebra matrices sp.spectral-theory determinants

Jul 6 '15 at 19:39 M. Lin 1,678

1

2

votes

1

answer

403

views

Is there some quantitative version of interlacing of eigenvalues of a matrix under rank-1 update?

fa.functional-analysis linear-algebra graph-theory convex-optimization spectral-graph-theory

May 30 '15 at 21:40 Dustin G. Mixon 6,456

2

votes

2

answers

395

views

Is anything known about the eigenspectrum of the regular representation of the permutation group?

reference-request rt.representation-theory matrices finite-groups unitary-representations

Apr 25 '15 at 0:44 Community♦ 1

1

2

votes

0

answers

170

views

Real-rooted polynomials and higher rank matrices

ag.algebraic-geometry cv.complex-variables polynomials real-algebraic-geometry multilinear-algebra

Feb 19 '15 at 18:18 Community♦ 1

1

2

votes

1

answer

148

views

Laplacian spectrum of $2-$lifts of graphs

linear-algebra graph-theory sp.spectral-theory spectral-graph-theory

Jan 15 '15 at 4:02 Chris Godsil 11.7k

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53 Questions

What is a “Ramanujan Graph”?

Are these three different notions of a graph Laplacian?

Is there a ``Ladner's Theorem" for the PH-vs-PSPACE scenario?

Are there exactly solvable CFTs?

What is a branched Riemann surface with cuts?

What methods do we have to understand the spectrum of matrices with restricted entries?

Constructing Ramanujan graphs from elliptic curves

When are (Abelian) Cayley graphs also expanders?

Do perfect matching(s) have signatures in the graph eigenvalues?

Matching polynomials and Ramanujan graphs

What do we know about isospectral Cayley graphs?

How does one go from convexity to submodularity?

Proof of the general expression for anomaly in a CFT and its partition function

About using the character formula for $SO(2n)$

Can one integrate around a branch-cut?

Reference request about the representations of the group $PSL_2(\mathbb{F}_q)$

Is there a method to simultaneously block-diagonalize a set of group matrices?

The Bilu-Linial conjecture and Ramanujan graphs

Can we count isospectral graphs?

What are Euler density and Weyl invariants?

About the second largest adjacency eigenvalue of Abelian Cayley graphs

About the small set expansion conjecture

The Fuchsian monodromy problem

Some identities with the Riemann-Hurwitz zeta function

About distinct eigenvalues of a graph

About adding a negative definite rank-1 matrix to a symmetric matrix

Is there some quantitative version of interlacing of eigenvalues of a matrix under rank-1 update?

Is anything known about the eigenspectrum of the regular representation of the permutation group?

Real-rooted polynomials and higher rank matrices

Laplacian spectrum of $2-$lifts of graphs