 There are other semantics for negation. One, due to Dunn, is a four-valued semantics. As is the case for truth tables for classical logic, this semantics begins with the values T (true) and F (false). A formula is given a set of these truth values. Thus, a formula \(A\) can get the values \(\{\True\}\), \(\{\False\}\), \(\{\True,\False\}\), or \(\varnothing\). If a formula gets the value \(\{\True\}\), then it is just true; likewise, if it gets the value \(\{\False\}\) it is just false; if it gets the value \(\{\True,\False\}\) it is both true and false; if it gets the value \(\varnothing\), it is neither true nor false.