 The line connecting two predicates, representing one and the same object, is called a line of identity by Peirce. That is, the sameness is represented visually in Beta  diagrams.[36]  In the case of a symbolic language, we may adopt one and the same quantified variable-type to represent the identity. For example, the above diagram says \(\exists x(x &lt;A \ \land \ B &lt; x)\), and hence, the variable-type \(x\) (roughly) corresponds to the identity line. However, the same variable-type is not sufficient for expressing the sameness in other cases, e.g., \(\exists x(x &lt;A \ \land \ B &lt; x) \rightarrow \exists x (x &lt; C)\).