-% \theoremstyle{plain}
-% \theoremheaderfont{\normalfont\bfseries\sc}
-% \theorembodyfont{\slshape}
-% \theoremsymbol{\ensuremath{\diamondsuit}}
-% \theoremprework{\bigskip}
-% \theoremseparator{.}
-\newtheorem{Def}{\underline{Définition}}
-\newtheorem{Lemma}{\underline{Lemme}}
-\newtheorem{Theo}{\underline{Théorème}}
-% \theoremheaderfont{\sc}
-% \theorembodyfont{\upshape}
-% \theoremstyle{nonumberplain}
-% \theoremseparator{}
-% \theoremsymbol{\rule{1ex}{1ex}}
-\newtheorem{Proof}{Preuve :}
-\newtheorem{xpl}{Exemple illustratif :}
+
+
+\newcommand {\tv}[1] {\lVert #1 \rVert_{\rm TV}}
+\def \top {1.8}
+\def \topt {2.3}
+\def \P {\mathbb{P}}
+\def \ov {\overline}
+\def \ts {\tau_{\rm stop}}
+
+
+\newtheorem{Def}{Definition}
+%\newtheorem{Lemma}{\underline{Lemma}}
+\newtheorem{Theo}{Theorem}
+\newtheorem{Corollary}{Corollary}
+\newtheorem{Lemma}{Lemma}
+\newtheorem{proposition}{Proposition}
+\newtheorem*{xpl}{Running Example}