```
% pandoc -f latex -t native
\newtheorem{theorem}{Theorem}
\newtheorem{corollary}[theorem]{Corollary}
\newtheorem{lemma}[theorem]{Lemma}
\theoremstyle{definition}
\newtheorem{definition}[theorem]{Definition}
\theoremstyle{remark}
\newtheorem{remark}{Remark}

\begin{definition}[right-angled triangles] \label{def:tri}
A \emph{right-angled triangle} is a triangle whose sides of length~\(a\), \(b\) and~\(c\), in some permutation of order, satisfies \(a^2+b^2=c^2\).
\end{definition}

\begin{lemma}
The triangle with sides of length~\(3\), \(4\) and~\(5\) is right-angled.
\end{lemma}

\begin{proof}
This lemma follows from \cref{def:tri} since \(3^2+4^2=9+16=25=5^2\).
\end{proof}

\begin{theorem}[Pythagorean triplets] \label{thm:py}
Triangles with sides of length \(a=p^2-q^2\), \(b=2pq\) and \(c=p^2+q^2\) are right-angled triangles.
\end{theorem}

\begin{remark}
These are all pretty interesting facts.
\end{remark}
^D
[ Div
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    [ Para
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        , Emph [ Str "right-angled triangle" ]
        , Str " is a triangle whose sides of length\160"
        , Math InlineMath "a"
        , Str ", "
        , Math InlineMath "b"
        , Str " and\160"
        , Math InlineMath "c"
        , Str ", in some permutation of order, satisfies "
        , Math InlineMath "a^2+b^2=c^2"
        , Str "."
        ]
    ]
, Div
    ( "" , [ "lemma" ] , [] )
    [ Para
        [ Strong [ Str "Lemma 2" ]
        , Str ".  "
        , Emph
            [ Str "The triangle with sides of length\160"
            , Math InlineMath "3"
            , Str ", "
            , Math InlineMath "4"
            , Str " and\160"
            , Math InlineMath "5"
            , Str " is right-angled."
            ]
        ]
    ]
, Div
    ( "" , [ "proof" ] , [] )
    [ Para
        [ Emph [ Str "Proof." ]
        , Str " This lemma follows from "
        , Link
            ( ""
            , []
            , [ ( "reference-type" , "ref" )
              , ( "reference" , "def:tri" )
              ]
            )
            [ Str "Definition\160\&1" ]
            ( "#def:tri" , "" )
        , Str " since "
        , Math InlineMath "3^2+4^2=9+16=25=5^2"
        , Str ".\160\9723"
        ]
    ]
, Div
    ( "thm:py" , [ "theorem" ] , [] )
    [ Para
        [ Strong [ Str "Theorem 3" ]
        , Str " (Pythagorean triplets).  "
        , Emph
            [ Str "Triangles with sides of length "
            , Math InlineMath "a=p^2-q^2"
            , Str ", "
            , Math InlineMath "b=2pq"
            , Str " and "
            , Math InlineMath "c=p^2+q^2"
            , Str " are right-angled triangles."
            ]
        ]
    ]
, Div
    ( "" , [ "remark" ] , [] )
    [ Para
        [ Emph [ Str "Remark 1" ]
        , Str ".  These are all pretty interesting facts."
        ]
    ]
]
```