Apparently, this user prefers to keep an air of mystery about them.
34 How did “normal” come to mean “perpendicular”? jun 26 '14
14 Is the class of additive groups of rings axiomatizable? mar 29 '12
13 Automorphisms of $P(\Bbb N)$ nov 12 '13
6 For a monoid with zero $M$, how many additive operations on $M$ can there be making $M$ a ring? apr 30 '13
4 Sets of natural numbers such that sums of a bounded number of its elements form a semigroup apr 15
3 dual composition of binary relations nov 19