Definition 4.7.3.1. Let $\kappa $ be a cardinal. We say that a set $S$ is $\kappa $-small if the cardinality $|S|$ is strictly smaller than $\kappa $.
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Definition 4.7.3.1. Let $\kappa $ be a cardinal. We say that a set $S$ is $\kappa $-small if the cardinality $|S|$ is strictly smaller than $\kappa $.