Markov product of positive definite kernels and applications to $Q$-matrices of graph products
Volume 122 / 2011
Colloquium Mathematicum 122 (2011), 177-184
MSC: Primary 05C50; Secondary 05C12, 43A35, 81S25.
DOI: 10.4064/cm122-2-2
Abstract
We show positivity of the $Q$-matrix of four kinds of graph products: direct product (Cartesian product), star product, comb product, and free product. During the discussion we give an alternative simple proof of the Markov product theorem on positive definite kernels.
