Combinatorial characterization of pseudometrics

O. Dovgoshey, J. Luukkainen

Let $X$, $Y$ be sets and let $\Phi$, $\Psi$ be mappings with the domains $X^2$ and $Y^2$ respectively. We say that $\Phi$ is combinatorially similar to $\Psi$ if there are bijections $f \c…