Manolo Martínez writes: > On 03/30/16 at 01:40pm, Jussi Piitulainen wrote: >> Manolo Martínez writes: > > >> > I think it's with your definition of surjection. Bijections are >> > surjective, no? >> >> Yes, and most many-to-one mappings are *not* surjective. > > Well, I don't know about most, there are uncountably many surjective > and non-surjective many-to-one mappings :)
Ok, safer to say that some many-to-one mappings are not surjective. I was thinking of finite sets, and not even really thinking. But even with infinite domain and infinite codomain, there can be uncountably many mappings without any of them being a surjection - just have the codomain be a larger infinity. It depends on the types. Which makes the concept not easily applicable to Python data structures as such. -- https://mail.python.org/mailman/listinfo/python-list
