# Czechoslovak Mathematical Journal

## Vol. 65, No. 4, 2015 · Contents

Samuel Littig, Jürgen Voigt:
Porous medium equation and fast diffusion equation as gradient systems

Qingyi Zeng:
On generalized CS-modules

Cheng Gong, Zhongming Tang:
A note on the multiplier ideals of monomial ideals

Han Zhang, Wenpeng Zhang:
Some new sums related to D. H. Lehmer problem

On the tree structure of the power digraphs modulo $n$

Nela Milošević, Zoran Z. Petrović:
Order complex of ideals in a commutative ring with identity

José María Grau, Antonio M. Oller-Marcén, Manuel Rodríguez, Daniel Sadornil:
Fermat test with Gaussian base and Gaussian pseudoprimes

A note on infinite $aS$-groups
$AF$-algebras and topology of mapping tori