2AC3 Conventions

Focus on Decision Problems
Inputs will generally be in the form of a string

symbols use
a, b, c, d symbols / letters
u, v, w, x, y, z strings
α,β,χ patterns
A, B, C, D, sets of strings

Alphabet, Σ : a finite set of symbols

String: a finite sequences of symbols
x=abc
x=ε - null string, string of no length

Operations on a String