Combinatorial results for semigroups of order-preserving partial transformations

A. Laradji, A. Umar*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 Citations (SciVal)


Let POn be the semigroup of all order-preserving partial transformations of a finite chain. It is shown that POn =cn satisfies the recurrence (2n-1)(n+1)cn+1=4 (3n2-1 cn-(2n+1) (n-1)cn-1 with initial conditions c0=1, c1=2. It is also shown that E(POn) =en satisfies the recurrence en+1=5(en-en-1)+1 with initial conditions e0=1, e1=2. Moreover, the cardinalities of the Green's relations L, R and J have been computed.

Original languageEnglish
Pages (from-to)342-359
Number of pages18
JournalJournal of Algebra
Issue number1
Publication statusPublished - Aug 1 2004
Externally publishedYes

ASJC Scopus subject areas

  • Algebra and Number Theory


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