Seta de ponta dupla com símbolo superior em Tikz

Question

Como posso escrever este diagrama no Tikz:

Aqui está minha tentativa:

\begin{tikzcd}
x \arrow{leftrightarrow}{r}{*} \arrow[dashed]{dr}{*} & &  
y \arrow[dashed]{dl}{*}  \\
& z &
\end{tikzcd}

Answer 1

Solução possível:

\documentclass[tikz]{standalone}
\usepackage{tikz-cd}

\begin{document}

\begin{tikzcd}
x \arrow[rr, leftrightarrow, "*"] \arrow[dr, dashrightarrow, "*"'] 
 &  & y \arrow[dl, dashrightarrow, "*"] \\
 & z &
\end{tikzcd}

\end{document}

---

Editar:Outra solução com Tik puroZ:

\documentclass[tikz]{standalone}

\begin{document}

\begin{tikzpicture}
 \node (x) at (0,0) {$x$};
 \node (y) at (2,0) {$y$};
 \node (z) at (1,-1) {$z$};

 \draw[<->] (x) -- node[above] {$\ast$} (y);
 \draw[->,dashed] (x) -- node[below left] {$\ast$} (z);
 \draw[->,dashed] (y) -- node[below right] {$\ast$} (z);
\end{tikzpicture}

\end{document}

Answer 2

\documentclass{article}
\usepackage{tikz}
\usepackage{tikz-cd}

\begin{document}

\begin{tikzcd}
x \arrow[dashed,"*"']{dr}\arrow[leftrightarrow]{rr}{*} & & y \arrow[dashed]{dl}{*}\\
& z &
\end{tikzcd}

\end{document}

Answer 3

Uma solução tikz simples:

\documentclass[tikz]{standalone}
\usetikzlibrary{positioning}
\begin{document}
\begin{tikzpicture}
  \draw[<->] (0,0) node[left] {$x$}--(4,0) node[midway, above]{$*$} node[right]{$y$};
  \draw[->,dashed] (0,0)--(2,-1.7) node[midway,below left]{$*$} node[below]{$z$};
  \draw[->,dashed] (4,0)--(2,-1.7) node[midway,below right]{*};
\end{tikzpicture}
\end{document}

Saída: