Sparks, Athena On the number of clonoids. (English) Zbl 1436.08005 Algebra Univers. 80, No. 4, Paper No. 53, 10 p. (2019). A clonoid \(C_{A,B}\) is a set of finitary functions from a set \(A\) to a set \(B\) that is closed under taking minors. The author studies the size of clonoids for finite sets and algebras. For any finite set \(A\) and any two-element algebra \(B\), \(C_{A,B}\) is finite iff \(B\) has an NU-term, it is countably infinite iff \(B\) has a Mal’cev term but no majority term and it has size continuum otherwise. If \(A\) is a finite set and \(B\) a finite idempotent algebra then \(C_{A,B}\) has size continuum iff \(B\) has no cube term. If \(B\) has a cube term, then there are countably many such clonoids. Reviewer: Ivan Chajda (Přerov) Cited in 1 ReviewCited in 3 Documents MSC: 08A40 Operations and polynomials in algebraic structures, primal algebras 06E30 Boolean functions Keywords:clones; polymorphisms; Boolean functions; minors; clonoids; NU-function; cube function PDF BibTeX XML Cite \textit{A. Sparks}, Algebra Univers. 80, No. 4, Paper No. 53, 10 p. (2019; Zbl 1436.08005) Full Text: DOI arXiv OpenURL References: [1] Aichinger, E.; Mayr, P., Finitely generated equational classes, J. Pure Appl. Algebra, 220, 2816-2827 (2016) · Zbl 1354.08004 [2] Baker, KA; Pixley, AF, Polynomial interpolation and the Chinese remainder theorem for algebraic systems, Math. Z., 143, 165-174 (1975) · Zbl 0292.08004 [3] Brakensiek, Joshua; Guruswami, Venkatesan, Promise Constraint Satisfaction: Structure Theory and a Symmetric Boolean Dichotomy, 1782-1801 (2018), Philadelphia, PA · Zbl 1403.68074 [4] Bulatov, A.: On the number of finite Mal’tsev algebras. Contributions to General Algebra. 13 (Velké Karlovice, 1999/Dresden, 2000), pp. 41-54. Heyn, Klagenfurt (2001) [5] Foster, AL, The identities of–and unique subdirect factorization within–classes of universal algebras, Math. Z., 62, 171-188 (1955) · Zbl 0064.26301 [6] Lau, D.: Function Algebras on Finite Sets. A Basic Course on Many-Valued Logic and Clone Theory. Springer Monographs in Mathematics. Springer, Berlin (2006) · Zbl 1105.08001 [7] Marković, P.; Maróti, M.; McKenzie, R., Finitely related clones and algebras with cube terms, Order, 29, 345-359 (2012) · Zbl 1310.08002 [8] Pippenger, N., Galois theory for minors of finite functions, Discrete Math., 254, 405-419 (2002) · Zbl 1010.06012 This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. It attempts to reflect the references listed in the original paper as accurately as possible without claiming the completeness or perfect precision of the matching.