Generating countable sets of surjective functions
J. D. Mitchell ; Y. Péresse
Fundamenta Mathematicae, Tome 215 (2011), p. 67-93 / Harvested from The Polish Digital Mathematics Library

We prove that any countable set of surjective functions on an infinite set of cardinality ℵₙ with n ∈ ℕ can be generated by at most n²/2 + 9n/2 + 7 surjective functions of the same set; and there exist n²/2 + 9n/2 + 7 surjective functions that cannot be generated by any smaller number of surjections. We also present several analogous results for other classical infinite transformation semigroups such as the injective functions, the Baer-Levi semigroups, and the Schützenberger monoids.

Publié le : 2011-01-01
EUDML-ID : urn:eudml:doc:283006
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     title = {Generating countable sets of surjective functions},
     journal = {Fundamenta Mathematicae},
     volume = {215},
     year = {2011},
     pages = {67-93},
     zbl = {1238.20070},
     language = {en},
     url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-fm213-1-4}
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J. D. Mitchell; Y. Péresse. Generating countable sets of surjective functions. Fundamenta Mathematicae, Tome 215 (2011) pp. 67-93. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-fm213-1-4/