2016-06-16 14:37 GMT+02:00 Steve Awodey : > They are exactly the same spheres Hey! It is extremely surprising to me that someone within this community believes this. My point was rather that you have to make clear, outside the community, that the theorems we talk about are new theorems, not just new (fancy?) ways to revisit the proof of old theorems. Now I understand that the job starts within the community. I am afraid of the discussion which could follow if I try to argue that the synthetic sphere is definitely different of the classical one... Sorry! andré H