typo

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

sec/acknowledgments.tex

@@ -8,7 +8,7 @@ I cannot help expressing the deepest gratitude to Harold: even though he was not
 He is surely a brilliant scientist and a great collaborator, but if he is not first of all a friend then I do not know who can be.
 I also wish to thank Marco and Carlo for all the support they gave me whenever they could and the advice they provided at all times.
 
-Life as a Ph.D.\ student would have been incredibly tough were it not for the great people who were with me all the time.
+Life as a graduate student would have been incredibly tough were it not for the great people who were with me all the time.
 I was not yet officially inside my Ph.D.\ programme when Alberto welcomed me to the office and showed me how to survive as a student and get the most from the experience as a person.
 Even though he will not admit it, Riccardo helped me to discover dedication in the darkest moments, while contextually Giovanni taught me how to bring light and humanity in those, in the face of adversities.
 In all this, with his silence \emph{à la Piemontese}, Francesco represented the needed balance.

sec/part1/introduction.tex

@@ -42,7 +42,7 @@ While Nambu and Goto's formulation is fairly direct in its definition, it is usu
   \eta_{\mu\nu}.
   \label{eq:conf:polyakov}
 \end{equation}
-The \eom for the string $X^{\mu}\qty(\tau, \sigma)$ is therefore:
+The \eom for the string $X^{\mu}\qty(\tau, \sigma)$ are therefore:
 \begin{equation}
   \frac{1}{\sqrt{- \det \gamma}}\,
   \ipd{\alpha}