  Over the past 10 years, there has been considerable interest in exploring
questions connecting dimension for posets with graph theoretic properties of
their cover graphs and order diagrams, especially with the concepts of
planarity and treewidth. Joret and Micek conjectured that if $P$ is a poset
with a planar cover graph, then the dimension of $P$ is bounded in terms of the
number of minimal elements of $P$ and the treewidth of the cover graph of $P$.
We settle this conjecture in the affirmative by strengthening a recent
breakthrough result [14] by Blake, Micek, and Trotter, who proved that for each
poset $P$ admitting a planar cover graph and a unique minimal element we have
$\mathrm{dim}(P) \leq 2 \mathrm{se}(P) + 2$, namely, we prove that
$\mathrm{dim}(P) \leq 2 \mathrm{wheel}(P) + 2$.
