# MATHEMATICA BOHEMICA

## Vol. 125, No. 4, 2000 · Contents

S. R. Grace, H. A. El-Morshedy:
On the oscillation of certain difference equations

A tree as a finite nonempty set with a binary operation

Jan Jakubik:
Graph automorphisms of semimodular lattices

Florian Luca:
On the equation $\phi(|x^m-y^m|)=2^n$

Locally regular graphs

Emilia Haluskova:
Monounary algebras with two direct limits

Ivan Chajda:
Characterizing binary discriminator algebras

Jiri Rachunek:
Ordered prime spectra of bounded $DRl$-monoids