In the fall of 1959 I went to Paris and spent the year there from- well first of all I was in the summer I was at Imperial College in London where everybody was interested in Yang-Mills theory, Salam and Kumar were working on the project that I mentioned. Then around the end of October I moved to Paris where I was at the Collége de France - I was, I think, the first visiting professor in the history of the Collége de France. And then I also had a job at the university, initially the university job was actually involved having an office at the École Normale which is not part of the university. But in the spring the campus at Orsée was established and my university office was out there in Orsée. So I spent some time at the College and some time at Orsée. Maurice Levy and I collaborated all during the year, and also Jeremy Bernstein came over from the US and he worked with me for a while. Fubini and Thirring both came by and we worked with them a little bit for a few days, and so there were papers signed with these various collaborators during the year.
What we were working on, from our point of view, was very similar to what Nambu and collaborators were working on from their point of view, and Goldstone from his point of view. Namely: what happened if you had an axial vector charge that was nearly conserved but did not lead to degeneracy, to approximate degeneracy? It would instead lead to a nearly massless pseudo-scalar boson. And so we thought about that; we called it partially conserved axial vector current; we looked at it from many different points of view; pole dominance and so on and so forth.
But from these various points of view that we investigated, it was the same idea, and in the limit of perfect conservation of the axial charge without producing degeneracy, it would produce an exactly zero mass boson. So it was the same really as the Nambu Goldstone boson.