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: http://www.mccme.ru/conf_feb_05/zvonkine.html
Дата изменения: Tue Feb 15 16:55:07 2005 Дата индексирования: Tue Oct 2 00:39:03 2012 Кодировка: Поисковые слова: cygnus loop |
We explain why the enumeration of ramified coverings of the sphere provides a model of 2-dimensional gravity. We show how to obtain the values of observables of 2-dimensional gravity using the asymptotic of the number of ramified coverings. We also prove some combinatorial results concerning ramified coverings of the sphere. The algebra of power series generated by \sum q^n n^n/n! and \sum q^n n^{n-1}/n! plays an important role. It appears naturally in elementary graph enumeration problems, in the intersection theory on moduli spaces of stable curves, and in the enumeration of ramified coverings.