We have the following indirect implication of form equivalence classes:

16 \(\Rightarrow\) 32
given by the following sequence of implications, with a reference to its direct proof:

Implication Reference
16 \(\Rightarrow\) 352 On first and second countable spaces and the axiom of choice, Gutierres, G 2004, Topology and its Applications.
352 \(\Rightarrow\) 32 Disasters in metric topology without choice, Keremedis, K. 2002, Comment. Math. Univ. Carolinae

Here are the links and statements of the form equivalence classes referenced above:

Howard-Rubin Number Statement
16:

\(C(\aleph_{0},\le 2^{\aleph_{0}})\):  Every denumerable collection of non-empty sets  each with power \(\le  2^{\aleph_{0}}\) has a choice function.

352:

A countable product of second countable spaces is second countable.

32:

\(C(\aleph_0,\le\aleph_0)\): Every denumerable set of non-empty countable sets  has a choice function.

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