Modified some figures

Signed-off-by: Riccardo Finotello <riccardo.finotello@gmail.com>

sec/part1/introduction.tex

@@ -233,15 +233,13 @@ In fact a transformation $\xi \mapsto \chi(\xi)$ and $\bxi \mapsto \bchi(\bxi)$
   \centering
   \begin{subfigure}[b]{0.45\linewidth}
     \centering
-    \def\svgwidth{\linewidth}
-    \import{img}{complex_plane.pdf_tex}
+    \import{tikz}{complex_plane.pgf}
     \caption{Radial ordering.}
   \end{subfigure}
   \hfill
   \begin{subfigure}[b]{0.45\linewidth}
     \centering
-    \def\svgwidth{\linewidth}
-    \import{img}{radial_ordering.pdf_tex}
+    \import{tikz}{radial_ordering.pgf}
     \caption{Difference of time ordered contours.}
   \end{subfigure}
   \caption{Map to the complex plane.}
@@ -1284,16 +1282,14 @@ The field $\cA^a$ forms a vector representation of the group \SO{D-1-p} and from
   \centering
   \begin{subfigure}[b]{0.45\linewidth}
     \centering
-    \def\svgwidth{0.8\linewidth}
-    \import{img}{chanpaton.pdf_tex}
+    \import{tikz}{chanpaton.pgf}
     \caption{Chan-Paton factors labelling strings.}
   \end{subfigure}
   \hfill
   \begin{subfigure}[b]{0.45\linewidth}
     \centering
-    \def\svgwidth{0.7\linewidth}
-    \import{img}{quark.pdf_tex}
-    \caption{Naive model of a left handed massive quark.}
+    \import{tikz}{quark.pgf}
+    \caption{Naive model of left handed massive quarks.}
   \end{subfigure}
   \caption{Strings attached to different D-branes.}
   \label{fig:dbranes:chanpaton}
@@ -1346,8 +1342,7 @@ The light spectrum is thus composed of the desired matter content alongside with
 
 \begin{figure}[tbp]
   \centering
-  \def\svgwidth{0.7\linewidth}
-  \import{img}{smbranes.pdf_tex}
+  \import{tikz}{smbranes.pgf}
   \caption{%
     Example of \sm-like construction using intersecting D-branes with the indications of the hypercharge $Y$.
     Perpendicular angles are only a matter of convenience: they are in principal arbitrary.