In an email exchange I had with C.A.R. Hoare a couple of years back he said: Paradoxically, I have been working on shared variable concurrency, using a partial

In an email exchange I had with C.A.R. Hoare a couple of years back he said: Paradoxically, I have been working on shared variable concurrency, using a partially ordered trace semantics. Until I retired, I was too frightened to tackle anything so difficult. Definitely life after 40, 50, 60, 70, ...