Leftwards Two Headed Arrow

The Leftwards Two Headed Arrow at U+219E is a left-pointing arrow with two arrowheads, used to show a strong or specialized leftward mapping, implication, or direction. It belongs to the Arrows block, a set of symbols for directional notation beyond ordinary punctuation. Its main real-world use is in mathematics, especially in logic, category theory, algebra, and diagrammatic notation, where arrow shape can carry meaning chosen by the author. A two-headed arrow commonly suggests a surjective map or an epimorphism; the leftward form may be used when the mapping is being read from right to left, as in B ↞ A to indicate a surjection from A onto B under a convention that places the target on the left. It also appears in technical diagrams, formal semantics, and academic writing where authors need a distinct leftward arrow that is not easily confused with a simple “goes to” arrow. Outside specialist notation it is uncommon, so in plain prose, signage, or user-interface labels a standard left arrow is usually clearer.