Topological pair

In the context of topology, a "topological pair" typically refers to a pair consisting of a topological space and a subset of that space, often denoted as \((X, A)\), where \(X\) is a topological space and \(A\) is a subset of \(X\). This concept is particularly useful in algebraic topology and can be used to study various properties of spaces and the relationship between spaces and their subspaces.