Uppercase

In some contexts, it is conventional to use one case only. For example, engineering design drawings are typically labelled entirely in uppercase letters, which are easier to distinguish individually than the lowercase when space restrictions require very small lettering. In mathematics, on the other hand, uppercase and lowercase letters denote generally different mathematical objects, which may be related when the two types of cases of the same letter are used; for example, x may denote an element of a setX.