% common-notions.tex — Euclid's five common notions (axioms of magnitudes). \section*{Common Notions} \label{sec:common-notions} \begin{rrxivremark}[Common Notion~1] \label{cn:1} Things which are equal to the same thing are also equal to one another. \end{rrxivremark} \begin{rrxivremark}[Common Notion~2] \label{cn:2} If equals be added to equals, the wholes are equal. \end{rrxivremark} \begin{rrxivremark}[Common Notion~3] \label{cn:3} If equals be subtracted from equals, the remainders are equal. \end{rrxivremark} \begin{rrxivremark}[Common Notion~4] \label{cn:4} Things which coincide with one another are equal to one another. \end{rrxivremark} \begin{rrxivremark}[Common Notion~5] \label{cn:5} The whole is greater than the part. \end{rrxivremark}