A double-stroke rightward arrow symbol representing logical implication or surjective functions in mathematical logic and category theory.
Examples
Logical double implication between statements
A \Rrightarrow B \text{ means 'A strongly implies B'}
Natural transformation between functors in category theory
F \Rrightarrow G: \mathcal{C} \to \mathcal{D}
Group homomorphism inducing map between quotient groups
G/H \Rrightarrow G'/H' \text{ via } \phi