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JOURNALS // Zapiski Nauchnykh Seminarov POMI // Archive

Zap. Nauchn. Sem. POMI, 2019 Volume 481, Pages 125–135 (Mi znsl6782)

The absolute of the comb graph

P. P. Nikitinab

a St. Petersburg Department of Steklov Institute of Mathematics, St. Petersburg, Russia
b St. Petersburg State University, St. Petersburg, Russia

Abstract: In the 1970s R. Stanley introduced the comb graph $\mathbb{E}$ whose vertices are indexed by the set of compositions of positive integers and branching reflects the ordering of compositions by inclusion. A. Vershik defined the absolute of a $\mathbb{Z}_+$-graded graph as the set of all ergodic probability central measures on it. We show that the absolute of $\mathbb{E}$ is naturally parametrized by the space $\Omega = \{(\alpha_1, \alpha_2, \dots ) : \alpha_i \ge 0$, $\sum_i \alpha_i \le 1\}$.

Key words and phrases: comb graph, compositions, Martin boundary, ergodic central measures, absolute.

UDC: 519.217.72, 517.987

Received: 15.09.2019

Language: English



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