📚 Recommended Mathematics Books

Topology (Munkres)  |  General Topology (Engelking)  |  Counterexamples in Topology  |  Rudin's Analysis

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I’ve added to my book a new easy to prove theorem and its corollary:

Theorem If $latex f$ is a (co-)complete funcoid then $latex \mathrm{up}\, f$ is a filter.

Corollary

  1. If $latex f$ is a (co-)complete funcoid then $latex \mathrm{up}\, f = \mathrm{up} (\mathsf{RLD})_{\mathrm{out}} f$.
  2. If $latex f$ is a (co-)complete reloid then $latex \mathrm{up}\, f = \mathrm{up}\, (\mathsf{FCD}) f$.