 Konieczny and Pino Pérez consider a propositional language L built up from a finite set At of atomic propositions and the usual connectives \((\neg, \land, \lor , \rightarrow, \leftrightarrow )\). An interpretation is a total function \(At \rightarrow \{0, 1\}\) that assigns 0 (false) or 1 (true) to each atomic proposition. For example, if \(At =\{p, q, r\}\), then \((1, 0, 1)\) is the interpretation that assigns true to p and r and false to  q.[1]  Denote the set of all interpretations by \(W = \{0, 1\}^{At}\). For any formula \(\varphi \in L\), \(\mymod(\varphi) = \{\omega \in W | \omega \models \varphi\}\) denotes the set of models of \(\varphi\), i.e., the set of truth assignments that makes \(\varphi\) true. If we take the formula that expressed the contractual law in the doctrinal example, then \(\mymod((p\land q) \leftrightarrow r) = \{(1,1,1), (1, 0, 0), (0, 1, 0), (0,0,0)\}.\) As usual, a formula \(\varphi\) is consistent if it has at least a model, and a formula \(\varphi\) follows from a set of formulae \(\Phi\) if every interpretation that makes all formulae in \(\Phi\) true, makes also \(\varphi\) true.