Badious oeuvre can be succintly phrased in his slogan: mathematic is ontology.
Mathematics I understand. So the question really is the other part of his slogan. I take his 'is' to be normal and ordinary english verb fulfiling its notoriously ambiguous function. So what does he mean by Ontology? Is it say the same Ontology that Heidegger expounds on in his Being and Time. Is it process and active rather than static and stable? Whereas time is a contiuum, Badiou in his book prefers the event - a punctuation in time. Is this significant?