Here I document some of the more primitive relations, particularly those with names I use quite broadly, giving name (if any) and denotations which describe the relation.

- subsume
- = ({relations}: s←r;
r relates x to y

impliess relates x to y

:{relations})which relates s to r precisely if s agrees with r about everything r says, optionally saying more.

- reverse
- = ({relations}: r←s;
r relates x to y

iffs relates y to x

:{relations})which interchanges the rôles of

left

andright

. Transitive fixed points of reverse are described as equivalences. Not to be confused with ... - (: (: i+j+1 = n; f(i)←j |n) ← (:f|n) :{lists})
which

reverses

the order of entries in a list, in the sense [z,…,a] ← [a,…,z]. I studiously do not call this mappingreverse

, because I reserve that name for the mapping from relations to relations given above.