> 1) Domain is the domain whose values are domains. > > Is this ok?
This says that Domain contains itself as a value. > 2) A category is some specified subdomain (subset) of Domain? This doesn't explain what a category is, but only that all categories are contained in Domain and thus are called 'domain's. Unfortunately, that "specific subdomain of Domain" could be empty, so I don't know whether there are categories at all. ;-) > I.e. The subset of Domain corresponding to a category is given by the > domains which refer to specific categories in their definition. > 3) A subdomain need not be a proper subset, i.e. it can consist of all > of Domain as a whole. > > In set theory X is an element of the power set power(X). I think comparing subdomain with subset makes it clear enough for me. > 4) Category is the domain of categories, i.e. subdomains of Domain. As > such it corresponds to the concept of the power set of Domain. Don't you mean to an "element of the power set of Domain", i.e. Categoy is a subdomain/subset of Domain? > 5) Type is the category in Category corresponding to Domain. In other > words Type is Domain in Category. That sound like "Domain: Type". But we also have "Type: Category" and "Category \subdomain Domain". That says that "Type: Domain" is also OK. That looks all too circluar to me. > Just like X in power(X). >> Somehow I now have the impression that Aldor-Type and OpenAxiom-Type >> are different. > > Yes. According to my definition they are different. > >> That "Type" is a category in OpenAxiom would have never come to >> my mind in Aldor. > Type in OpenAxiom is like 'with {}' in Aldor. Until Saul Yousseph > presented his ideas on implementing mathematical category theory in > Aldor perhaps no one thought this category was particularly > interesting. But Saul defines Domain: Category == with so that is yet another occurence of "Domain". Would you say that in Aldor this Youssef-"Domain" is what "Type" is in panAxiom? Ralf ------------------------------------------------------------------------- Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 _______________________________________________ open-axiom-devel mailing list open-axiom-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/open-axiom-devel