Symbols:Abbreviations

Z
= N =

NNF

 * Negation normal form.

= O =

ODE

 * An ordinary differential equation.

= P =

PDE

 * A partial differential equation.

PGF or p.g.f.

 * Probability Generating Function.

PMF or p.m.f.

 * Probability mass function.

PNT

 * Prime Number Theorem.

= Q =


 * Q.E.D.

= R =

RHS

 * Right hand side.

In an equation:
 * $\textrm {Expression}\ 1 = \textrm {Expression}\ 2$

the term $\textrm {Expression}\ 2$ is the RHS.

= S =

SCF

 * Simple continued fraction.

SFCF

 * Simple finite continued fraction.

SICF

 * Simple infinite continued fraction.

= U =

UFD

 * Unique Factorization Domain.

URM

 * Unlimited Register Machine. An abstraction of a computing device with certain particular characteristics.

= W =

WFF

 * Well-formed formula.

WLOG

 * Without loss of generality.

Suppose there are several cases which need to be investigated.

If the same argument can be used to dispose of two or more of these cases, then it is acceptable in a proof to pick just one of these cases, and announce this fact with the words: Without loss of generality, ..., or just WLOG.

WRT

 * With respect to.

When performing calculus operations, i.e. differentiation or integration, one needs to announce which variable one is "working with".

Thus the phrase with respect to is (implicitly or explicitly) part of every statement in calculus.

The abbreviation WRT or w.r.t. is frequently seen, and often pronounced something like wurt.

= Z =

ZF

 * Zermelo-Fraenkel Set Theory.

ZFC

 * Zermelo-Fraenkel Set Theory with the Axiom of Choice.