Publications de l'Institut Mathématique publishes papers by Yugoslav and foreign mathematicians in all branches of pure and applied mathematics. The new series of Publications continues the series formed by Volumes I to XIV of Publications de l'Institut Mathématique de l'Académie Serbe des Sciences et des Arts.

Publications is sent to institutions and scientific societies willing to send in exchange other publications to the Mathematical Institute.

Authors will receive 50 offprints.

Correspondence should be addressed to

Publications de l'Institut Mathématique
Matematički institut
Kneza Mihaila 35
11001 Beograd, p.p. 367

The annual subscription rate (2 volumes) is 100 USD. For foreign subscriptions write to

Kubon & Sagner
Buchexport-Import GMBH
D-80328 München


Manuscripts should be submitted in three copies. They are expected not to exceed 16 printed pages. Each paper should be accompanied by an abstract and should bear the five-character AMS subject classification code (2000).

Formulas should be displayed only if they must be enumerated for future reference or if they are too long or complicated. Please do not enumerate formulas which are not referred to.

A new paragraph should not be started if this is not necessary. Paragraphs of one or two lines (one or two sentences) are possible, of course, but they should be exceptional, not usual.

Only standard abbreviations for names of journals (see Zentralblatt MATH) should be used in references.

If you prepare your manuscript on a computer, then we suggest using TeX. If you prepare figures or illustrations on a computer, then please send them in a form of .PCX or .BMP file (each figure or illustration in a separate file). Make sure that they fit into the dimensions of the text of our journal (printed with resolution of 600 dpi).

ISSN 0350-1302