A geometric symbol representing a square shape, commonly used in logic for end-of-proof notation or modal operators.
Examples
End of proof notation (QED symbol)
\text{Therefore, } x^2 + y^2 = z^2 \square
Modal logic necessity operator
\square p \rightarrow p \text{ (axiom of modal logic)}
Square operator in mathematics
\text{Let } \square A \text{ denote the square of matrix } A