Countable cellularity of arbitrary products via finite subproducts
An arbitrary product of topological spaces satisfies the countable chain condition (CCC) whenever every finite subproduct does. For nonempty factors this is an equivalence. The proof includes an indexed uncountable delta-system lemma that permits repeated finite supports, and glues compatible cylinders over a finite common root. Arbitrary products of separable spaces are consequently CCC, without a cardinal bound or separation assumptions and allowing empty factors. Continuous-surjection preservation and the discrete-space countability criterion are proved companions. No unrestricted…
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