Productivity and wages in a task-based model
I guess you are referring to a situation in which abundand supply of high-skilled workers decrease productivity such that individual $w_h &lt; w_l$
Considering Equation (5) in Acemoglu &amp; Autor, $H$ and $L$ capture supply of both groups of workers. If $\frac{H}{L}$ becomes sufficiently high, I don't see why the relation between both wages should not become lower than 1.