The Tbilisi Mathematical Journal (TMJ) is a fully refereed international journal, publishing original research papers in all areas of mathematics. The Editorial Board of TMJ consists of well-known international experts in the fields covering most important areas of mathematics. The editors and a rigorous refereeing procedure will ensure the highest international standards and quality. The Editorial Board may occasionally decide to invite the submission of survey and expository papers of the highest quality. Unsolicited submissions of survey and expository papers will not be considered for publication.