We need a more abstract way to define reloids: For example filters on a set $latex A\times B$ are isomorphic to triples $latex (A;B;f)$ where $latex f$ is a filter on $latex A\times B$, as well as filters of boolean reloids (that…

read moreThere were several errors in the section “Open maps” of my online book. I have rewritten this section and also moved the section below in the book text. However, the new proof of the theorem stating that composition of open maps between…

read moreBible, John 3:16: (CJB) “For God so loved the world that he gave his only and unique Son, so that everyone who trusts in him may have eternal life, instead of being utterly destroyed.” (ISV) “For this is how God loved the…

read moreThe below is wrong, because pointfree funcoids between boolean algebras are not the same as 2-staroids between boolean algebras. It was an error. I have just discovered that the set of ideals on an infinite join-semilattice is a boolean algebra (moreover it…

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