User Brendan McKay

43 votes

3 answers

2k views

History of the four-colour problem

asked Jan 12, 2012 at 11:38

38 votes

3 answers

4k views

finding the parity of a permutation in little space

asked Aug 11, 2011 at 8:50

31 votes

4 answers

2k views

Probability of zero in a random matrix

asked Jun 3, 2012 at 10:52

26 votes

1 answer

1k views

probability of zero subset sum

asked Jan 21, 2013 at 12:59

25 votes

3 answers

1k views

Changing the signs of the coefficients of a polynomial to make all the roots real

asked Dec 19, 2016 at 7:03

23 votes

1 answer

1k views

Jumping in the integers

asked Sep 4, 2011 at 4:47

21 votes

1 answer

1k views

A strange sum over bipartite graphs

asked Mar 5, 2012 at 7:00

21 votes

2 answers

2k views

Largest graphs of girth at least 6

asked Jun 16, 2012 at 4:16

18 votes

4 answers

2k views

Complexity of equitable partitions

asked May 13, 2012 at 23:34

17 votes

0 answers

495 views

Maximum automorphism group for a 3-connected cubic graph

asked Jul 17, 2013 at 1:29

16 votes

1 answer

2k views

Overlapping Gershgorin disks

asked Aug 13, 2011 at 13:38

14 votes

1 answer

406 views

A Collatz-like question about permutations

asked Aug 5, 2015 at 1:17

12 votes

5 answers

563 views

Intersecting 4-sets

asked Nov 6, 2012 at 2:23

11 votes

0 answers

301 views

How many n/2-cycles can a cubic graph have

asked Oct 3, 2013 at 13:44

10 votes

1 answer

569 views

Maximal subgroups of a certain finite 2-group

asked Sep 2, 2012 at 8:15

10 votes

1 answer

390 views

Network flows with capacities on pairs of edges

asked May 24, 2012 at 14:54

9 votes

2 answers

351 views

Finding local patterns in a circular list

asked Feb 21, 2012 at 14:02

9 votes

2 answers

791 views

Need to bound a trigonometric sum

asked Aug 20, 2011 at 13:13

8 votes

3 answers

673 views

partly obscured Rubik's cube

asked Oct 10, 2012 at 3:12

8 votes

1 answer

688 views

6-regular bipartite graphs with no 8-cycles

asked Jul 29, 2012 at 10:55

8 votes

2 answers

1k views

Spanning trees of plane graphs containing an edge of every face

asked Nov 17, 2012 at 9:31

8 votes

1 answer

307 views

Factoring a multiset into a product of two multisets

asked Feb 7, 2016 at 1:22

8 votes

0 answers

152 views

Hamiltonian paths in the prime sum graph

asked Jul 9 at 5:41

7 votes

1 answer

202 views

What polytope is this? Bounded sums with choice of coefficients

asked Oct 11, 2015 at 4:53

7 votes

0 answers

178 views

How quickly can we test if a graph is distance-regular?

asked May 1, 2013 at 7:48

7 votes

1 answer

141 views

Covering a set with images of a transversal

asked Jan 12, 2015 at 9:07

7 votes

1 answer

219 views

A polytope with a bound on the sum of any $k$ variables

asked Dec 12, 2014 at 7:00

6 votes

0 answers

69 views

Digraph weak connectivity in $O(V)$ space and $O(V+E)$ time

asked Jun 22, 2015 at 16:30

6 votes

0 answers

249 views

Does anyone know this determinant?

asked Jan 16, 2015 at 3:17

6 votes

1 answer

367 views

Asymptotic value of a multivariate integral

asked Nov 25, 2013 at 10:32

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55 Questions

History of the four-colour problem

finding the parity of a permutation in little space

Probability of zero in a random matrix

probability of zero subset sum

Changing the signs of the coefficients of a polynomial to make all the roots real

Jumping in the integers

A strange sum over bipartite graphs

Largest graphs of girth at least 6

Complexity of equitable partitions

Maximum automorphism group for a 3-connected cubic graph

Overlapping Gershgorin disks

A Collatz-like question about permutations

Intersecting 4-sets

How many n/2-cycles can a cubic graph have

Maximal subgroups of a certain finite 2-group

Network flows with capacities on pairs of edges

Finding local patterns in a circular list

Need to bound a trigonometric sum

partly obscured Rubik's cube

6-regular bipartite graphs with no 8-cycles

Spanning trees of plane graphs containing an edge of every face

Factoring a multiset into a product of two multisets

Hamiltonian paths in the prime sum graph

What polytope is this? Bounded sums with choice of coefficients

How quickly can we test if a graph is distance-regular?

Covering a set with images of a transversal

A polytope with a bound on the sum of any $k$ variables

Digraph weak connectivity in $O(V)$ space and $O(V+E)$ time

Does anyone know this determinant?

Asymptotic value of a multivariate integral