# How to stop numbering the word proof in my document and to put the square at the end of my proofs?

Here is my document from the beginning:

\documentclass{book}
\usepackage[margin=1in]{geometry}
\usepackage{datetime2}
\usepackage{lipsum}

\DTMsetstyle{mmddyy}
\DTMsetup{datesep=/}

\usepackage{fancyhdr}
\pagestyle{fancy}

\usepackage{tcolorbox}
\tcbuselibrary{theorems}
\newtcbtheorem[auto counter, number within=section]{problem}{Problem}{
fonttitle=\bfseries,
colframe=black,
coltitle=black,
colback=black!10,
colbacktitle=black!10,
boxrule=.4pt,
attach title to upper=\newline,
sharp corners,
top=1mm, bottom=1mm,
left=2mm, right=2mm,
}{}
\newtheorem{pro}{\emph{Proof}}
\begin{document}

%\begin{center}
% \sffamily
%Title
%\end{center}

\setcounter{chapter}{7}
\setcounter{section}{2}
\begin{problem}[phantom=\setcounter{\tcbcounter}{13}]{}{}
\lipsum[1]
\end{problem}

\begin{pro}

\end{pro}

\end{document}



But I am wondering how can I stop numbering the word proof in my document and to put the square at the end of my proofs?

Any help will be greatly appreciated!

EDIT:

Here is how my document looks like now:

You may use add these two lines before this line \newtheorem{pro}{\emph{Proof}} in your code to serve your purpose.

\usepackage{ntheorem}
\theoremstyle{nonumberplain}


EDIT:

Another solution can be proposed:

\usepackage{amssymb}
\usepackage[thmmarks]{ntheorem}
\theoremsymbol{$\blacksquare$}

• @Happy I have edited the answer with the solution of the square at the end of each proof.
If you load the amsthm package it will give you a proof environment that will do what you want (although there are some special cases, such as when your proof ends with a displayed equation or a list where you will need to use \qedhere to produce the proof box at the correct location.
• It did not ... amsthm Oct 31 '21 at 4:33