[chrisseaton]

> parallelism require concurrency

I don't think it does. For example in a SIMD system there is parallelism, but no concurrency. Operations are being performed in parallel, but there is only a single program (SI..) and no concurrent tasks.

[bullen]

I think you have to add "Joint" Parallel as a definition of two separate cores that collaborate on the same data at the same time - that requires concurrent memory/disc access. That Erlang can't provide BTW.

[arethuza]

Or the same single threaded executable running as two processes on different cores/cpus - there is parallelism but no concurrency within any of the processes?

[zzzcpan]

Still, different pieces of hardware execute the same instruction on different data. Think of this as data concurrency if you like.