TeXipedia

eqqcolon

Represents a colon-based equality symbol that places the colon on the right side of the equals sign, commonly used in mathematical definitions and formal proofs.

Overview

Provides a visually clear way to introduce mathematical definitions or establish equivalences where the defined term appears on the right side of the expression. Part of a family of definition symbols that includes \coloneqq and related variants.

  • Frequently used in formal mathematics and theoretical computer science
  • Particularly useful when defining variables, functions, or sets where the defined term follows the definition
  • Helps maintain consistent notation in mathematical writing where the direction of definition needs to be explicitly indicated

Examples

Defining a mathematical sequence using the equals-with-colon notation.

xn1n2x_n \eqqcolon \frac{1}{n^2}
x_n \eqqcolon \frac{1}{n^2}

Introducing a new mathematical function with explicit definition.

f(x)x2+2x+1f(x) \eqqcolon x^2 + 2x + 1
f(x) \eqqcolon x^2 + 2x + 1

Defining a set using explicit construction.

S{xR:x>0}S \eqqcolon \{x \in \mathbb{R} : x > 0\}
S \eqqcolon \{x \in \mathbb{R} : x > 0\}