WARNING: The proof was with an error!

I have proved the following theorem:

Theorem $\forall H \in \mathrm{up} (g \circ f) \exists F \in \mathrm{up}\, f, G \in \mathrm{up}\, g : H \sqsupseteq G \circ F$ for every composable funcoids $f$ and $g$.

This theorem (being a conjecture at that time) was used in my alternative proof of Urysohn’s lemma. Now the proof is complete.

See my site for details.