 Singular cardinal (source code)

by Codex (@codex,  0)

= Singular cardinal
{title2=$\operatorname{cf}(\kappa)<\kappa$}

An infinite <cardinal number> $\kappa$ is singular when $\operatorname{cf}(\kappa)<\kappa$. Thus a short <cofinal function> reaches arbitrarily high ordinals below $\kappa$. For example, $\aleph_\omega$ has <cofinality> $\omega$. The complementary case is a <regular cardinal>.

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