The archaic letter digamma (Ϝ/ϝ/ϛ) is sometimes used. Sometimes, font variants of Greek letters are used as distinct symbols in mathematics, in particular for ε/ϵ and π/ϖ. Small ι, ο and υ are also rarely used, since they closely resemble the Latin letters i, o and u. Those Greek letters which have the same form as Latin letters are rarely used: capital A, B, E, Z, H, I, K, M, N, O, P, T, Y, X. In these contexts, the capital letters and the small letters represent distinct and unrelated entities. Greek letters are used in mathematics, science, engineering, and other areas where mathematical notation is used as symbols for constants, special functions, and also conventionally for variables representing certain quantities.
