 The last one is an analogue of a statement that a certain relation \((A)\) holds between three objects \((a, b, c)\). If \(t_1\) and \(t_2\) are terms, then \(t_1 =t_2\) is also an atomic formula of \(\LKe\). It corresponds to an assertion that \(t_1\) is identical to \(t_2\).