 Sometimes, the term "unit interval" is used to refer to objects that play a role in various branches of mathematics analogous to the role that [0,1] plays in homotopy theory.For example, in the theory of quivers, the (analogue of the) unit interval is the graph whose vertex set is {0,1} and which contains a single edge "e" whose source is 0 and whose target is 1.One can then define a notion of homotopy between quiver homomorphisms analogous to the notion of homotopy between continuous maps.