Semigroups [antikvár]

PREFACE The 11th conference in Szeged of the János Bolyai Mathematical Society was held from August 24 to 28, 1981, under the title "Semigroups. Structure and universal algebraic problems." There was a number of invited lectures and, besides, several 20 minute talks, most of which were connected with the topic given above. As in our earher volumes, we publish also papers by authors who were intended to present them at the conference but could not attend. Also, there was a problem session; the problems posed there can be found at the end of the volume. We ask everybody who makes some progress in solving them to let know about it one (or more) of the editors, in order that we can mention the result in our next semigroup volume. The Editors Q