Symbols

Σ (sigma) is a symbol for expressing sums of consecutive terms concisely. Lower index below, upper index above.

Π (capital pi) is a symbol for expressing products of consecutive terms. Often used in factorials and combinations.

∞ (infinity) represents the concept of unboundedness. Used in limits, integrals, and set theory.

∂ is used for differentiating multivariable functions with respect to one variable, treating others as constants.

Set notation includes symbols for sets and their operations: ∈, ⊆, ∪, ∩, etc.

∇ (nabla, del) is a vector differential operator. Used for gradient, divergence, and curl.

∫ is the integral sign, derived by Leibniz from an elongated S for 'Sum'.

∀ (universal quantifier) means 'for all', ∃ (existential quantifier) means 'there exists'. Used for precise mathematical statements.

n! (n factorial) is the product of all positive integers from 1 to n. Essential in permutations and combinations.

The binomial coefficient (n k) or ⁿCₖ is the number of ways to choose k items from n items. Also coefficients in binomial expansion.