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Kostochka and Thomason independently showed that any graph with average degree
$\Omega(r\sqrt{\log r})$
contains a
$K_r$
minor. In particular, any graph with chromatic number
$\Omega(r\sqrt{\log r})$
contains a
$K_r$
minor, a partial result towards Hadwiger’s famous conjecture. In this paper, we investigate analogues of these results in the directed setting. There are several ways to define a minor in a digraph. One natural way is as follows. A strong
$\overrightarrow{K}_{\!\!r}$
minor is a digraph whose vertex set is partitioned into r parts such that each part induces a strongly connected subdigraph, and there is at least one edge in each direction between any two distinct parts. We investigate bounds on the dichromatic number and minimum out-degree of a digraph that force the existence of strong
$\overrightarrow{K}_{\!\!r}$
minors as subdigraphs. In particular, we show that any tournament with dichromatic number at least 2r contains a strong
$\overrightarrow{K}_{\!\!r}$
minor, and any tournament with minimum out-degree
$\Omega(r\sqrt{\log r})$
also contains a strong
$\overrightarrow{K}_{\!\!r}$
minor. The latter result is tight up to the implied constant and may be viewed as a strong-minor analogue to the classical result of Kostochka and Thomason. Lastly, we show that there is no function
$f\;:\;\mathbb{N} \rightarrow \mathbb{N}$
such that any digraph with minimum out-degree at least f(r) contains a strong
$\overrightarrow{K}_{\!\!r}$
minor, but such a function exists when considering dichromatic number.
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