An injective function, also known as a one-to-one function, is a type of function where each element in the domain maps to a unique element in the codomain. This means that no two different inputs produce the same output. For example, if f(a) = f(b) , then it must be true that a = b . Injective functions are important in mathematics because they preserve distinctness. They can be represented graphically, where a horizontal line intersects the graph at most once. This property is useful in various fields, including algebra and calculus, for understanding function behavior and relationships.