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Hajime Machida - Hyperclones on the two-element setzo



HAJIME MACHIDA, Hitsotsubasji University, Kunitachi, Tokyo  186-8601, Japan
Hyperclones on the two-element setzo


Recently, I. G. Rosenberg initiated the study of hyperoperations and hyperclones. For a set A, a hyperoperation on A is a mapping from $A \times\cdots\times A$ to the set of non-empty subsets of A and a hyperclone on A is a composition-closed set of hyperoperations. Here we study some basic properties of hyperoperations and hyperclones. In particular, we show that the lattice of hyperclones on the two-element set $\{0,1\}$ has the cardinality of continuum. This answers affirmatively to Rosenberg's problem posed in 1998.