Full Idea
Enlightened by the Cantorian grounding of mathematics, we can assert ontology to be nothing other than mathematics itself. This has been the case ever since its Greek origin.
Clarification
Cantorian mathematics concerns large infinite numbers
Gist of Idea
Ontology is (and always has been) Cantorian mathematics
Source
Alain Badiou (Briefings on Existence [1998], 1)
Book Reference
Badiou,Alain: 'Briefings on Existence', ed/tr. Madarsz,Norman [SUNY 2006], p.40
A Reaction
There seems to be quite a strong feeling among mathematicians that new 'realms of being' are emerging from their researches. Only a Platonist, of course, is likely to find this idea sympathetic.