What is borrowed ladder or degenerate?

A borrowed ladder, often referred to as a degenerate ladder in the context of graph theory or linear algebra, describes a scenario where a set of vectors (or edges in a graph) does not span the entire space or dimension they are intended to cover. This situation arises when there are linear dependencies among the vectors, making some of them redundant. As a result, the system lacks the necessary components to form a complete basis, leading to limitations in representation or computation.