👉 In mathematics, a sequence or function is said to be injective (or one-to-one) if each element of the codomain of the function maps to exactly one element in its domain. In other words, for every element in the domain, there exists an element in the codomain that maps to it. For example, consider the function f defined by f(x) = 2x + 1 for all x in R (the real numbers). This function is injective because for any
