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,