5 Jan
2021
5 Jan
'21
8:06 p.m.
Le mar. 5 janv. 2021 à 22:23, Allan Wechsler <acwacw@gmail.com> a écrit :
Oh, regarding Marc LeBrun's interesting speculations on the number of rings (or rngs) that can be built with a given additive structure:
remember that addition is required to be commutative in rngs.
Are there any abelian groups that support no rngs?
No: you can always define x*y = 0 for all x,y, and get a ring (without unit, what some call a rng... ;-)) - Maximilian