Drawing a Hasse diagram in latex

Question

I am currently trying to draw the followig hasse diagram in Latex. From my undertsanding i think i should be using the tikzcd pacakge but having trouble getting undertstanding how it works. I would be grateful for any help.

Thank you in advance.

Answer 1

Here is a way to do it:

\documentclass{article}
\usepackage{amssymb} 
\usepackage{tikz-cd}
\begin{document}
\begin{tikzcd}[row sep=1.5cm, column sep=1.7cm]
& A \
{a, b}\urar & {a, c}\uar \arrow[from=dr]& {b, c}\ular \
{a }\uar\urar & {b}\ular[crossing over] \urar[crossing over] & { c} \uar\
 & \varnothing\ular\uar \urar
  \end{tikzcd} %
\end{document}