Bestiary of primitives

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 implies s 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 iff s relates y to x :{relations})

which interchanges the rôles of left and right. 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 mapping reverse, because I reserve that name for the mapping from relations to relations given above.

Bulk Actions and Binary Operators