Changes

\section{Transitional remarks}

\section{Transitional remarks}

\textbf{Temporary Note.}  The remainder of this discussion uses the syntax for propositional calculus that is described in the entry on minimal negation operators.  Logical negation is written by enclosing an expression in parentheses, for example, $(x)$ is $\lnot x.$  Logical conjunction is written by concatenating expressions in the manner of algebraic products, for example, $x\ y\ z$ is $x \land y \land z.$  For the time being, further details can be found in the entry just mentioned.

\textbf{Temporary Note.}  The remainder of this discussion uses the syntax for propositional calculus that is described in the entry on minimal negation operators.  Logical negation is written by enclosing an expression in parentheses, for example, $(x)$ is $\lnot x.$  Logical conjunction is written by concatenating expressions in the manner of algebraic products, for example, $x\ y\ z$ is $x \land y \land z.$  See Table A1 in \PMlinkname{Appendix 1}{DifferentialPropositionalCalculusAppendices} for equivalent expressions in this syntax and several others for the 16 propositional forms on two variables.

\section{Formal development}

\section{Formal development}