\usepackage{lmodern}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{mathtools}
\usepackage{parskip}
\usepackage[dvipsnames]{xcolor}
\usepackage{tcolorbox}
\usepackage{hyperref}
\usepackage{geometry}
\usepackage{physics}
\usepackage{systeme,mathtools}
\usepackage[usestackEOL]{stackengine}
\usepackage{scalerel}
\usepackage{graphicx}
\usepackage{enumerate}
\usepackage{tikz}
\usepackage[labelfont=bf]{caption}
\usepackage[separate-uncertainty=true]{siunitx}
\usepackage{cancel}
\usepackage{fancybox}
\usepackage{multicol}
\usepackage{amsthm}
\usepackage[shortlabels]{enumitem}
\usepackage{float}
\usetikzlibrary{positioning}
\geometry{top=25mm}

% Plantilla per l'interior d'un conjunt
\newcommand{\interior}[1]{%
  {\kern0pt#1}^{\mathrm{o}}%
}

% Plantilles del notate
\def\myupbracefill#1{\rotatebox{90}{\stretchto{\{}{#1}}}
\def\rlwd{.5pt}
\newcommand\notate[4][B]{%
  \if B#1\else\def\myupbracefill##1{}\fi%
  \def\useanchorwidth{T}%
  \setbox0=\hbox{$\displaystyle#2$}%
  \def\stackalignment{c}\stackunder[-6pt]{%
    \def\stackalignment{c}\stackunder[-1.5pt]{%
      \stackunder[2pt]{\strut $\displaystyle#2$}{\myupbracefill{\wd0}}}{%
    \rule{\rlwd}{#3\baselineskip}}}{%
  \strut\kern9pt$\rightarrow$\smash{\rlap{$~#4$}}}%
}
\newcommand\lnotate[4][B]{%
  \if B#1\else\def\myupbracefill##1{}\fi%
  \def\useanchorwidth{T}%
  \setbox0=\hbox{$\displaystyle#2$}%
  \def\stackalignment{c}\stackunder[-6pt]{%
    \def\stackalignment{c}\stackunder[-1.5pt]{%
      \stackunder[2pt]{\strut $\displaystyle#2$}{\myupbracefill{\wd0}}}{%
    \rule{\rlwd}{#3\baselineskip}}}{%
  \strut\kern-9pt$\leftarrow$\smash{\llap{$~#4\quad\;\,$}}}%
}

% Plantilles dels boxes
%%%% START DEFINING LBOXED, RBOXED %%%%
\newcommand{\lboxed}[1]{\fbox[blt]{\mathsurround=0pt$\displaystyle#1$}}
\newcommand{\rboxed}[1]{\fbox[brt]{\mathsurround=0pt$\displaystyle#1$}}

% Plantilles pels problemes
\newcounter{problem}
\newcounter{solution}

\newcommand{\green}[1]{\textbf{\color{ForestGreen} #1}}

\newcommand{\separator}{\noindent\hfil\rule{0.75\textwidth}{0.4pt}\hfil}

% Versió impresora:
\newif\ifprintversion

\newenvironment{Problem}{%
    \stepcounter{problem}%
    \ifprintversion
      \begin{tcolorbox}[colback=white!10!white,parbox=false]
    \else
      \begin{tcolorbox}[colback=cyan!10!white,parbox=false]
    \fi
        \textbf{Problema \theproblem.}~%
        \setcounter{solution}{0}}{%
    \end{tcolorbox}
}

\newenvironment{FreeProblem}{%
    \ifprintversion
      \begin{tcolorbox}[colback=white!10!white,parbox=false]
    \else
      \begin{tcolorbox}[colback=cyan!10!white,parbox=false]
    \fi
        \setcounter{solution}{0}}{%
    \end{tcolorbox}
}

\newcommand\Solution{%
    \textbf{Solució:}\\%
}

\newcommand\Context{%
    \textbf{Context:}\\%
}

\newcommand\Lema{%
    \textbf{Lema:} %
}

\newcommand\Proposition{%
    \textbf{Proposició:} %
}

\newcommand\Theorem{%
    \textbf{Teorema:} %
}

\newcommand\Proof{%
    \textbf{Demostració:}\\%
}

\newcommand\QED{\square}

\newcommand\ASolution{%
    \stepcounter{solution}%
    \textbf{Solució \thesolution:}\\%
}


\newcommand{\asection}[2]{
\setcounter{section}{#1}
\addtocounter{section}{-1}
\section{#2}
}

% Tensor commands:
\newcommand*{\TT}[1]{\bar{\bar{#1}}}
\newcommand*{\dev}[0]{\text{dev}\,}

% Corrections:
\newif\ifshowcorrections

\newcommand{\correction}[1]{%
  \ifshowcorrections%
    {\color{red} #1}%
  \else%
    #1%
  \fi%
}%

\newcommand{\formulacorrection}[1]{%
  \ifshowcorrections%
    \textcolor{red}{#1}%
  \else%
    #1%
  \fi%
}%