Suppose the government wants to sell broadcasting rights in two areas: North and South.
The Vickrey–Clarke–Groves (VCG) algorithm finds the socially-optimal allocation, which is to give both areas to Alice.
Both auction types are truthful - no single agent could gain by reporting a different value.
In contrast, the DAA will reject Alice, then accept Bob and Carl, and charge each of them his threshold price, which is $3M.
[2] An application of this idea in a double auction setting was outlined by then-Stanford computer science researchers including Tim Roughgarden in 2014 that same year.