NAMING CONVENTIONS FOR METAVARIABLES

A,B    : arity
C      : candidate of reducibility
D,E    : RTM environment
F,G    : global environment 
H      : reserved: transient premise
IH     : reserved: inductive premise
I,J    : item
K,L    : local environment
M,N    : reserved: future use
O,P,Q  :
R      : generic predicate (relation)
S      : RTM stack
T,U,V,W: term
X,Y,Z  : reserved: transient objet denoted by a capital letter

a,b    :
c      : local dropping kind parameter (true = restricted, false = general)
d      : term degree
e      : reserved: future use (\lambda\delta 3)
f,g    : local reference transforming map 
h      : sort hierarchy parameter
i,j    : local reference depth (de Bruijn's)
k,l    : global reference level
m      : 
n      : type iterations
o      : sort degree parameter
p,q    : binder polarity
r      : reduction kind parameter (true = ordinary, false = extended)
s      : sort index
t,u    :
v,w    : local reference position level (de Bruijn's) (RTM)
x,y,z  : reserved: transient objet denoted by a small letter

NAMING CONVENTIONS FOR CONSTRUCTORS

0: atomic
2: binary

A: application to vector
F: boolean false
T: boolean true

a: application
b: binder
d: abbreviation
f: flat
l: abstraction
n: native type annotation

NAMING CONVENTIONS FOR TRANSFORMATIONS AND RELATED FORMS

- prefix and first letter

b: bi contex-sensitive for local environments
c: contex-sensitive for terms
f: context-freee for closures
l: sn contex-sensitive for local environments
r: dx contex-sensitive for local environments
s: stratified (prefix) 
t: context-free for terms

- second letter

e: reserved for generic entrywise extension
i: irreducible form
n: normal form
p: reflexive parallel transformation
q: sequential transformation
r: reducible form
s: strongly normalizing form

- third letter

b: (q)rst-reduction
c: conversion
d: decomposed rt-reduction
e: decomposed rt-conversion
q: restricted reduction
r: reduction
s: substitution
u: supclosure
w: reserved for generic pointwise extension
x: rt-reduction
y: rt-substitution

- forth letter (if present)

c: proper single step (general)                (successor)
e: reflexive transitive closure to normal form (evaluation)
g: proper multiple step (general)              (greater)
p: non-reflexive transitive closure            (plus)
q: reflexive closure                           (question)
r: proper multiple step (restricted)           (restricted)
s: reflexive transitive closure                (star)
u: proper single step (restricted)             (unit)