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Keywords:
monounary algebra; retract; cardinality
monounary algebra; retract; cardinality
Summary:
For an uncountable monounary algebra $(A,f)$ with cardinality $\kappa $ it is proved that $(A,f)$ has exactly $2^{\kappa }$ retracts. The case when $(A,f)$ is countable is also dealt with.
References:
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