Chris Godsil
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 15h comment Existence of a $d$-regular graph such that $|N_G(x) \cap N_G(y)| = \lambda$. The Latin square graph constructed from a $6\times6$ Latin square has parameter $(36,15;6,6)$. 1d comment Cut Space of Vertices without Orthogonal Complement of Cycle Space? You are confusing "orthogonal complement", which is a linear algebra concept and which applies here, withe the graph theory "complement", which does not apply here. 2d reviewed Close List the partitions of the set $S = \{1, 2, 3\}$. 2d reviewed Close Give me your opinion about those books 2d reviewed Close Probability Help with finding mean and variance of estimators 2d reviewed Close Particle locating/collision prediction in bounded (two-dimensional) environments 2d reviewed Close A question involving logarithms; How to solve? 2d reviewed Close Is it unitary matrix or not? 2d reviewed Close How can I convert this second order equation into a first order equation? 2d reviewed Close Multiplying boths sides of an equation by $\frac{1}{x}$ 2d reviewed Close Cardinality of set of infinite subsets of $\mathbb{N}$ 2d reviewed Close Confusion of intersection of two 2-d planes in 4-d 2d reviewed Close Using Serre's Theorem, and showing lie algebra is 1-D Apr 29 reviewed Close How to calculate the total number of dissimilar terms (terms having different powers in x)… Apr 29 reviewed Close Example of a non-measurable set for which the outer measure is known Apr 29 reviewed Close Find the number of ways of coloring pentagonal faces of the dihedral in three colors. Apr 28 comment Do $A$ and $B$ have the same eigenvalues? @M.S.: If Hermitian matrices commute then they have the same eigenvectors (more precisely, they can be simultaneously diagonalized). Their eigenvalues will not be the same unless the matrices are equal. Apr 28 comment Do $A$ and $B$ have the same eigenvalues? @M.S.: My last claim does not require $A$ and $B$ to be Hermitian. I included it because I thought that the false claim might be a mixed up version of this statement. Apr 28 comment Do $A$ and $B$ have the same eigenvalues? $AA^2- A^2A= A^3-A^3 = 0$. Apr 28 comment undirected unweighted graphs having $1$ as an eigenvalue In a word: No. But since they're not classified, it is difficult to provide a reference.