| For example, consider the proposition <math>f\!</math> of concrete type <math>f : X \times Y \times Z \to \mathbb{B}</math> and abstract type <math>f : \mathbb{B}^3 \to \mathbb{B}</math> that is written <math>\texttt{(} x, y, z \texttt{)}</math> in cactus syntax. Taken as an assertion in what Peirce called the ''existential interpretation'', <math>\texttt{(} x, y, z \texttt{)}</math> says that just one of <math>x, y, z\!</math> is false. It is useful to consider this assertion in relation to the conjunction <math>xyz\!</math> of the features that are engaged as its arguments. A venn diagram of <math>\texttt{(} x, y, z \texttt{)}</math> looks like this: | | For example, consider the proposition <math>f\!</math> of concrete type <math>f : X \times Y \times Z \to \mathbb{B}</math> and abstract type <math>f : \mathbb{B}^3 \to \mathbb{B}</math> that is written <math>\texttt{(} x, y, z \texttt{)}</math> in cactus syntax. Taken as an assertion in what Peirce called the ''existential interpretation'', <math>\texttt{(} x, y, z \texttt{)}</math> says that just one of <math>x, y, z\!</math> is false. It is useful to consider this assertion in relation to the conjunction <math>xyz\!</math> of the features that are engaged as its arguments. A venn diagram of <math>\texttt{(} x, y, z \texttt{)}</math> looks like this: |