TeXipedia

isin

Denotes set membership, indicating that an element belongs to a specified set in mathematical notation.

Overview

Essential for expressing mathematical relationships in set theory, abstract algebra, and general mathematical proofs.

  • Commonly used in defining mathematical sets and their properties
  • Appears frequently in formal mathematical definitions and theorems
  • Fundamental in discrete mathematics and computer science for describing data structures
  • Often paired with other set notation symbols for complex set relationships

Examples

Expressing set membership for a single element.

xRx \isin \mathbb{R}
x \isin \mathbb{R}

Stating that a number belongs to a specific interval.

y[0,1]y \isin [0,1]
y \isin [0,1]

Defining membership in a set using set-builder notation.

z{x:x>0 and x<5}z \isin \{x : x > 0 \text{ and } x < 5\}
z \isin \{x : x > 0 \text{ and } x < 5\}