# How to put therefore and implies symbols

\documentclass{article}
\usepackage{graphicx}

\begin{document}
\vspace{\baselineskip}\noindent
\textbf{THEOREM :} If an operator has both Left Identity and Right Identity then it is \emph{UNIQUE}.
\vspace{\baselineskip}\noindent
\textbf{PROOF :} Let e_{l} is left identity
therefore e_{l} * e_{r}
this implies e_{r}
\end{document}

• Welcome to TeX.SX! Please make your code compilable, starting with \documentclass{...} and ending with \end{document}. That may seem tedious to you, but think of the extra work it represents for TeX.SX users willing to help you. Help them help you: remove that one hurdle between you and a solution to your problem. – Ronny Nov 6 '13 at 10:40
• It would be nice, if you could explain, what you tried to include the symbols, where they should appear, and whether you need that in more than this small example (because then maybe it's better to use algorithm2e or something like that). – Ronny Nov 6 '13 at 11:08
• i want to write symbol for "therefore" – user39495 Nov 6 '13 at 11:10
• If you are using \vspace font changes or \noindent in a document it is a sign that something is probably wrong. Ideally the markup should just be \begin{theorem} with the spacing and fonts specified elsewhere. – David Carlisle Nov 6 '13 at 11:12
• the three dots symbol is $\therefore$ (amssymb package) see texdoc symbols – David Carlisle Nov 6 '13 at 11:14

As stated in the comments, you get the symbols in mathmode simply by writing them down. Packages like amsmath and amssymb support you.

\documentclass{article}
\usepackage{amsmath}
\usepackage{amssymb}
\newtheorem{theorem}{THEOREM}
\newtheorem{proof}{PROOF}
\begin{document}
\begin{theorem}
If an operator has both Left Identity and
Right Identity then it is \emph{UNIQUE}.
\end{theorem}
\begin{proof}
Let $e_{l}$ is left identity
$\therefore e_{l} * e_{r} \implies e_{r}$
\end{proof}
\end{document}


• With a very fierce “don't do it in a printed document”! – egreg Mar 21 '15 at 15:57
• I think you're missing an amsthm somewhere. – kahen Mar 21 '15 at 20:31
• @kahen Can you explain why? Did you run my example? – Johannes_B Mar 22 '15 at 9:49

A somewhat larger version of \therefore may be built as:

\dot{.\hspace{.095in}.}\hspace{.5in}


• That sort of tricks may be OK for visual rendering but they can be highly undesirable when trying to copy raw text from a generated PDF – JuanRocamonde Dec 29 '18 at 22:46

Maybe you could simply use lualatex and a font which actually has the character:

%!TEX TS-program = lualatex
\documentclass{article}
\usepackage{fontspec}
\newtheorem{theorem}{THEOREM}
\newtheorem{proof}{PROOF}
\begin{document}
\begin{theorem}
If an operator has both Left Identity and
Right Identity then it is \emph{UNIQUE}.
\end{theorem}
\begin{proof}
Let $e_{l}$ is left identity
∴ $e_{l} * e_{r}$ ⇒ $e_{r}$
\end{proof}
\end{document}


Initialisation Code:

\def\therefore{\boldsymbol{\text{ }
\leavevmode
\lower0.4ex\hbox{$\cdot$}
\kern-.5em\raise0.7ex\hbox{$\cdot$}
\kern-0.55em\lower0.4ex\hbox{$\cdot$}
\thinspace\text{ }}}


And can then be called on using:

\therefore


Which renders as:

Not entirely happy with any of the handmade therefores proposed above, I thought would offer this one also, which in my opinion has a good balance of dot size (in between \bullet and \cdot) and spacing:

\def\therefore{{\tiny$\bullet$}\kern-0.2ex\raisebox{1ex}{\tiny$\bullet$}\kern-0.2ex{\tiny$\bullet$}}