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Abstract. Let $\underline k$ denote a $k$-element chain, $k \geq3$. Let $M$ denote the clone generated by all unary isotone operations on $\underline k$ and let $\mathop{\rm Pol} \leq $ denote the clone of all isotone operations on $\underline k$. We investigate the interval of clones $[M, \mathop{\rm Pol} \leq ]$. Among other results, we describe completely those clones which contain only join (or meet) homomorphisms, and describe the interval completely for $k \leq4$.
AMS Subject Classification
(1991): 08A40, 03B50
Keyword(s):
clone,
isotone operations,
monoidal interval
Received October 11, 2000, and in revised form February 27, 2001. (Registered under 2827/2009.)
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