\documentclass[a4paper,leqno]{strayman}
\let\numberwithin=\notdef
+\usepackage{amsmath}
\usepackage{mathabx}
\usepackage{stmaryrd}
\usepackage{slashed}
\newcommand{\hasparents}{>_{\mkern-7.0mu _1}}
\newcommand{\areparents}{<_{\mkern-14.0mu _1\mkern+5.0mu}}
-\newcommand{\implies}{\Rightarrow}
+\renewcommand{\implies}{\Rightarrow}
\newcommand{\pancs}[2]{{\mathcal A} ( #1 , #2 ) }
\newcommand{\pends}[2]{{\mathcal E} ( #1 , #2 ) }
+\renewcommand{\land}{\wedge}
+
\begin{document}
\section{Notation}
is to be taken as applying to both $\py$ and $\pn$.
All these sets are distinct.
+\item[ $ \pancs{C}{\set P} $ ]
+$ \{ A \; | \; A \le C \land A \in \set P \} $
+i.e. all the ancestors of $C$
+which are in $\set P$.
+
+\item[ $ \pends{C}{\set P} $ ]
+$ \{ E \; | \; E \in \pancs{C}{\set P}
+ \land \mathop{\not\exists}_{A \in \pancs{C}{\set P}}
+ A \neq E \land E \le A \} $
+i.e. all $\le$-maximal commits in $\pancs{C}{\set P}$.
+
\end{basedescript}
\section{Invariants}
-$$ C \has D \implies C \ge D \eqno{No replay} $$
+\[ C \has D \implies C \ge D \tag*{\mbox{No replay:}} \]
Unique base: \[ \mathop{\forall}_{C \in \py} \pends{C}{\pn} = \{ B \} \]