Maxson, Carlton J. Semigroups of order preserving partial endomorphisms on trees. I. (English) Zbl 0269.20056 Colloq. Math. 32, 25-37 (1974). Page: −5 −4 −3 −2 −1 ±0 +1 +2 +3 +4 +5 Show Scanned Page MSC: 20M20 Semigroups of transformations, relations, partitions, etc. 06A06 Partial orders, general PDF BibTeX XML Cite \textit{C. J. Maxson}, Colloq. Math. 32, 25--37 (1974; Zbl 0269.20056) Full Text: DOI OpenURL