But it’s not a special case of non-Euclidian geometry, they’re disjoint.
(It seems like you’re using “non-Euclidian” to mean “any geometry that accepts the first 4 postulates”, but I think it actually means “any geometry that accepts the first 4 postulates but doesn’t accept the 5th”.)
Ah, yeah, that is totally fair. In that case I don’t have a great rephrasing. Maybe “Euclidian geometry was systematized into absolute geometry by removing the fifth postulate”, but honestly, I’ve never heard the term “absolute geometry” before I just googled this topic.
But it’s not a special case of non-Euclidian geometry, they’re disjoint.
(It seems like you’re using “non-Euclidian” to mean “any geometry that accepts the first 4 postulates”, but I think it actually means “any geometry that accepts the first 4 postulates but doesn’t accept the 5th”.)
Ah, yeah, that is totally fair. In that case I don’t have a great rephrasing. Maybe “Euclidian geometry was systematized into absolute geometry by removing the fifth postulate”, but honestly, I’ve never heard the term “absolute geometry” before I just googled this topic.