Abstract
The smallest finitely based semigroup currently known to generate a variety with continuum many subvarieties is of order seven. The present article introduces a new example of order six and comments on the possibility of the existence of a smaller example. It is shown that if such an example exists, then up to isomorphism and anti-isomorphism, it must be a unique monoid of order five.
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Dedicated to Professor Norman R. Reilly on the occasion of his 70th birthday.
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Edmunds, C.C., Lee, E.W.H. & Lee, K.W.K. Small Semigroups Generating Varieties with Continuum Many Subvarieties. Order 27, 83–100 (2010). https://doi.org/10.1007/s11083-010-9142-8
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DOI: https://doi.org/10.1007/s11083-010-9142-8