Brendan McKay's user avatar
Brendan McKay's user avatar
Brendan McKay's user avatar
Brendan McKay
  • Member for 13 years, 3 months
  • Last seen this week
43 votes
3 answers
2k views

History of the four-colour problem

38 votes
3 answers
4k views

finding the parity of a permutation in little space

31 votes
4 answers
2k views

Probability of zero in a random matrix

26 votes
1 answer
1k views

probability of zero subset sum

25 votes
3 answers
1k views

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

23 votes
1 answer
1k views

Jumping in the integers

21 votes
1 answer
1k views

A strange sum over bipartite graphs

21 votes
2 answers
2k views

Largest graphs of girth at least 6

18 votes
4 answers
2k views

Complexity of equitable partitions

17 votes
0 answers
495 views

Maximum automorphism group for a 3-connected cubic graph

16 votes
1 answer
2k views

Overlapping Gershgorin disks

14 votes
1 answer
406 views

A Collatz-like question about permutations

12 votes
5 answers
563 views

Intersecting 4-sets

11 votes
0 answers
301 views

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

10 votes
1 answer
569 views

Maximal subgroups of a certain finite 2-group

10 votes
1 answer
390 views

Network flows with capacities on pairs of edges

9 votes
2 answers
351 views

Finding local patterns in a circular list

9 votes
2 answers
791 views

Need to bound a trigonometric sum

8 votes
3 answers
673 views

partly obscured Rubik's cube

8 votes
1 answer
688 views

6-regular bipartite graphs with no 8-cycles

8 votes
2 answers
1k views

Spanning trees of plane graphs containing an edge of every face

8 votes
1 answer
307 views

Factoring a multiset into a product of two multisets

8 votes
0 answers
152 views

Hamiltonian paths in the prime sum graph

7 votes
1 answer
202 views

What polytope is this? Bounded sums with choice of coefficients

7 votes
0 answers
178 views

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

7 votes
1 answer
141 views

Covering a set with images of a transversal

7 votes
1 answer
219 views

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

6 votes
0 answers
69 views

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

6 votes
0 answers
249 views

Does anyone know this determinant?

6 votes
1 answer
367 views

Asymptotic value of a multivariate integral