c: conversion
d: decomposed extended reduction
e: decomposed extended conversion
-n: reduction for "big tree" normal forms
q: restricted reduction
r: reduction
s: substitution
u: supclosure
+w: reserved for generic pointwise extension
x: extended reduction
y: extended substitution
r: proper multiple step (restricted) (restricted)
s: reflexive transitive closure (star)
u: proper single step (restricted) (unit)
+x: reserved for generic pointwise extension