bio  website  quoll.uwaterloo.ca 

location  waterloo  
age  66  
visits  member for  5 years, 7 months 
seen  1 hour ago  
stats  profile views  3,395 
Professor at University of Waterloo in C&O
1d

reviewed  Close how to solve a linear equation (Axb)T lamda(c)? 
1d

reviewed  Close How to show that the mapping A is linear ? 
2d

reviewed  Close system of linear equations 
May 27 
answered  Graph classes which are not perfect but the stability number = clique cover numer? 
May 23 
reviewed  Close Searching for $C^*$ 
May 13 
reviewed  Leave Open Average degree of neighbors in a simple graph (> Friendship paradox) 
Apr 22 
reviewed  Close Anick resolution 
Apr 16 
reviewed  Leave Open Notation for the allones vector 
Apr 11 
reviewed  Close Integral closure of an ideal 
Apr 11 
awarded  graphtheory 
Apr 10 
comment 
Request for examples of 4regular, nonplanar, girth at least 5 graphs
@gordonRoyle: I was thinking there might be examples on fewer than 19 vertices? 
Apr 10 
answered  Request for examples of 4regular, nonplanar, girth at least 5 graphs 
Apr 7 
comment 
About the second largest adjacency eigenvalue of Abelian Cayley graphs
The matrix is $d\times m$ (say). There are $2^d$ binary vectors and they form a group of order $2^d$. The graphs we get is a Cayley graph for this group, with valency $m$. The problem is to compute the eigenvalues in time polynomial in $n$. 
Apr 7 
comment 
About the second largest adjacency eigenvalue of Abelian Cayley graphs
The vertices are binary vectors. Two vertices are adjacent if their difference is a column of the given matirx. 
Apr 1 
reviewed  Close If $(X_n+Y_n)$ has bounded variance, is the same true for $(X_n)$ and $(Y_n)$? 
Apr 1 
reviewed  Leave Open Dissolution of Tensors 
Mar 26 
reviewed  Leave Open Lovasz's Path removal conjecture 
Mar 24 
revised 
About the upper bound on the roots of the matching polynomial
removed ambiguity, fixed typo 
Mar 24 
comment 
About the upper bound on the roots of the matching polynomial
@user6818: I have edited my answer. I wrote "gives", which is ambiguous, now it's "divides". 
Mar 23 
comment 
About the upper bound on the roots of the matching polynomial
The reason your "following statement" is not in the paper is that it is not true. The paper shows that given a graph $G$ thrre is a tree $T$ such that the matching polynomial of $G$ divides the matching polynomial of $T$. But the matching polynomial of a tree is equal to its characteristic polynomial and the graph and the tree have the same maximum valency, so standard eigenvalue bounds on the tree give the bound on the zeros of matching polynomial of $G$. 