Igusa-Todorov functions for radical square zero algebras

We study the behaviour of the Igusa-Todorov functions for radical square zero algebras. We show that the left and the right $\phi$-dimensions coincide, in this case. Some general results are given, but we concentrate more in the radical square zero algebras. Our study is based on two notions of hearth and member of a quiver $Q$. We give some bounds for the $\phi$ and the $\psi$-dimensions and we describe the algebras for which the bound of $\psi$ is obtained. We also exhibit modules for which the $\phi$-dimension is realised.