## A NOTE ON JOINS OF ADDITIVE HEREDITARY GRAPH PROPERTIES

Ewa Drgas-Burchardt

Faculty of Mathematics, Computer Science and Econometrics
University of Zielona Góra
Prof. Z. Szafrana 4a, 65-516 Zielona Góra, Poland
e-mail: E.Drgas-Burchardt@wmie.uz.zgora.pl

## Abstract

Let La denote a set of additive hereditary graph properties. It is a known fact that a partially ordered set (La, ⊆ ) is a complete distributive lattice. We present results when a join of two additive hereditary graph properties in (La, ⊆ ) has a finite or infinite family of minimal forbidden subgraphs.

Keywords: hereditary property, lattice of additive hereditary graph properties, minimal forbidden subgraph family, join in the lattice.

2000 Mathematics Subject Classification: 05C75, 05C15, 05C35.

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