A specific approach to defining the property of a function, the concept centers on using convergent sequences. A function is continuous at a point if, for every sequence that converges to that point, the sequence of the function’s values at those points also converges, specifically to the function’s value at the original point. For instance, consider a function f(x) and a point c. If for every sequence xn that approaches c, the sequence f(xn) approaches f(c), then the function is continuous at c according to this definition.
This method provides a powerful alternative to the epsilon-delta definition, particularly when dealing with more abstract spaces where a notion of distance may not be readily available. Its benefits include its applicability in functional analysis and its direct connection to the concept of convergence, a fundamental tool in analysis. Historically, this definition arose as mathematicians sought more robust and general ways to express the idea of a function’s smoothness and connectedness, particularly in contexts beyond real-valued functions of a single real variable.