We define in the setting of homotopy type theory an H-space structure on S3. Hence we obtain a description of the quaternionic Hopf fibration S3 ↪→ S7 S4, using only homotopy invariant tools.

We show that there are two homotopy types of PD3 -complexes with fundamental group S3 ∗Z/2Z S3 , and give explicit constructions for each, which differ only in the attachment of the top cell. AMS Classification 57P10; 55M05

We define a natural partial exchangeability assumption for multi-class systems with Polish state spaces, under which we obtain results extending those for exchangeable systems: the conditional law of a finite system given the vector of the empirical measures of its classes corresponds to independent uniform permutations within classes, and the convergence in law of this vector is equivalent to ...

This paper proposes necessary and sufficient conditions for an additively separable representation of preferences in the Savage framework (where the objects of choice are acts: measurable functions from an infinite set of states to a potentially finite set of consequences). A preference relation over acts is represented by the integral over the subset of the product of the state space and the c...

I outline the power counting scheme recently introduced by M. Savage, M. Wise and myself for the effective field theory treatment of NN scattering. It is particularly useful for describing systems with a large scattering length, and differs from Weinberg’s power counting. A renormalization group analysis plays a big role in determining the order of a given operator. Pions are ignored in this di...