Guide to LaTeX (4th Edition) (Tools and Techniques

5.3.1 Greek letters
5.3. Mathematical symbols 125
Lower case letters
α \alpha θ \theta o o τ \tau
β \beta ϑ \vartheta π \pi υ \upsilon
γ \gamma ι \iota ϖ \varpi φ \phi
δ \delta κ \kappa ρ \rho ϕ \varphi
ɛ \epsilon λ \lambda ϱ \varrho χ \chi
ε \varepsilon µ \mu σ \sigma ψ \psi
ζ \zeta ν \nu ς \varsigma ω \omega
η \eta ξ \xi
Upper case letters
Γ \Gamma Λ \Lambda Σ \Sigma Ψ \Psi
∆ \Delta Ξ \Xi Υ \Upsilon Ω \Omega
Θ \Theta Π \Pi Φ \Phi
The Greek letters are made simply by putting the command character \
before the name of the letter. Upper case (capital) letters are distinguished
by capitalizing the first letter of the name. Greek letters that do not appear
in the above list are identical with some corresponding Latin letter. For
example, upper case ρ is the same as Latin P and so needs no special
symbol.
L AT E X normally sets the upper case Greek letters in Roman (upright)
type within a mathematical formula. If they need to be in italics, this
can be brought about with the math alphabet command \mathnormal:
$\mathnormal{\Gamma\Pi\Phi}$ appears as Γ ΠΦ.
Greek letters may only be used in math mode. If they are needed in
normal text, the command must be enclosed in $. . . $ signs.
5.3.2 Calligraphic letters
The following 26 calligraphic letters may also be used in math formulas:
A, B, C, D, E, F, G, H , I, J, K, L, M, N , O, P, Q, R, S, T, U, V, W, X, Y, Z
These are called with the math alphabet command \mathcal:
$\mathcal{A, B, C,...,Z}$
5.3.3 Binary operators
Two mathematical quantities combined with one another to make a new
quantity are said to be joined by a binary operation. The symbols that are
available for use as binary operators are