Unformalised

This category contains googological notions which have not been completely defined due to the fact that they have not been formalised in a reasonable theory such as Zermelo–Fraenkel set theory or its extensions which are believed to be consistent. For example, large functions only admitting intuitive descriptions or intended behaviours are suitable for this category. For formalised systems including unsolved problems in the definitions, see Category:Unsolved problems. For formalised systems including serious errors or serious ambiguities in the definitions, see Category:Incomplete.