∑ "is a symbol in mathematics. Pronunciation is "belonging". If a∈A, then A belongs to set A, and A is an element in set A. When reading this symbol in mathematics, it can be directly expressed by the word "belonging".

Common expressions:

A ∈ R: A is a∈R:a number; A ∈ n: A is a non-negative integer (natural number).

In solid geometry, the symbol "∈" is used to represent a point (note! For points only) and the positional relationship between a line and a plane.

Example: A∈l means that point A is on a straight line L; A∈α means that point A is on plane α.

Extended data

Mathematical symbol:?

1, sign of quantity: for example, I, 2+i, A, X, natural logarithm base E, pi.

2. Operation symbols: such as plus sign (+), minus sign (-), multiplication sign (× or), division sign (÷ or/), union of two sets (∩), intersection (∩), root sign (√), logarithm (log, lg, ln).

3. relational symbols: for example, = is equal sign, ≈ is approximate sign, ≠ is unequal sign, > is greater than sign,