\documentclass{article}

\usepackage{amsmath,amsthm,amsfonts}
\usepackage[colorlinks=true, linkcolor=blue]{hyperref}
\usepackage{linkedthm}

% Define base environment
\newtheorem{theorem}{Theorem}

% Declare linked version
\DeclareLinkedTheorem{linkedtheorem}{theorem}{Theorem}

\begin{document}

\section*{linkedthm Example}

This is a simple test of the \texttt{linkedthm} package.

\begin{linkedtheorem}{thm:positivity}
For any real number \( x \), we have \( x^2 \geq 0 \).
\end{linkedtheorem}

\begin{linkedproof}{thm:positivity}
Squaring a real number always yields a non-negative result:
\[
x^2 = x \cdot x \geq 0.
\]
\end{linkedproof}

\end{document}