Avevo provato, ma mi restituisce l’errore in allegato.
copio il mio preambolo
`\documentclass{beamer}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[italian]{babel}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{amsthm}
\usepackage{enumerate}
\newtheorem{teo}{Teorema}
\newtheorem{cor}[teo]{Corollario}
\newtheorem{remark}{Osservazione}[subsection]
\newtheorem{prop}[teo]{Proposizione}
\newtheorem{lem}[teo]{Lemma}
\newtheorem{defi}{Definizione}
\title[titolo corto]{Titolo della tesi esteso}
\subtitle{Sottotitolo della tesi}
\author{Autore}
\institute[Uni]{Università}
\usetheme
{Goettingen} %{Pittsburgh} %alternativa con barra laterale a sinistra
\useoutertheme{infolines}
\usecolortheme{rose}
\usecolortheme{seahorse}
\useinnertheme{circles}
%\usefonttheme{structuresmallcapsserif} %per cambiare il font dei titoletti
%\setbeamertemplate{headline}[default] %per togliere la barra sopra
\makeatletter
% Sidebar
\setbeamersize{sidebar width \beamer@sidebarside=\beamer@sidebarwidth}
\setbeamertemplate{sidebar \beamer@sidebarside}
{
\beamer@tempdim=\beamer@sidebarwidth%
\advance\beamer@tempdim by -6pt%
\insertverticalnavigation{\beamer@sidebarwidth}%
\vfill
\ifx\beamer@sidebarside\beamer@lefttext%
\else%
\usebeamercolor{normal text}%
\llap{\usebeamertemplate***{navigation symbols}\hskip0.1cm}%
\vskip2pt%
\fi%
}%
\ifx\beamer@sidebarside\beamer@lefttext%
\defbeamertemplate*{sidebar right}{sidebar theme}
{%
\vfill%
\llap{\usebeamertemplate***{navigation symbols}\hskip0.1cm}%
\vskip2pt}
\fi
\makeatother
\setbeamertemplate{blocks}[rounded]
\setbeamercovered{dynamic}
\mode
`