Add figure on boundary orientation

Signed-off-by: Marcello Seri <[email protected]>

7-integration.tex

@@ -277,6 +277,9 @@ \section{Orientation on manifolds}
 
 Let's first look at the tangent space. 
 If $M$ ia a smooth $n$-manifold with boundary and $p\in \partial M$, we have three types of possible vectors:
+\begin{marginfigure}
+  \includegraphics{images/8_2-boundary-vectors.pdf}
+\end{marginfigure}
 \begin{enumerate}
   \item tangent boundary vectors: $X\in T_p(\partial M)\subset T_p M$ tangent to the boundary, forming an $(n-1)$-dimensional subspace of $T_p M$;
   \item inward pointing vectors: $X\in T_pM$ such that $X = \varphi^{-1}_*(Y)$ where $\varphi^{-1}: V\subset \cH^n \to M$ and $Y$ is some vector $Y = (Y_1, \ldots, Y_n)$ with $Y_n > 0$;