binary mekso operator: form quotient space X1/X.
This word generates/outputs quotient space Q = X1/X. X1 is an algebraic structure. X2 is a subset of the set underlying X1 such exactly and all of the elements of X2 are those elements which are treated as equalling the relevant identity element (0) in Q (when there is ambiguity, then 0 is the additive identity element in Q). X2 is the equivalence class of 0 in Q; thus, X2 can also be denoted by an equivalence relation. Closely related to "vei'e", "vei'u".