Vow contract represents the Dai Credit System's balance sheet. In particular, the
Vow acts as the recipient of both the system surplus and system debt. Its main functions are to cover deficits via debt (
Flop) auctions and discharge surpluses via surplus (
sin: the system debt queue.
Sin: the total amount of debt in the queue.
Ash: the total amount of on-auction debt.
wait: length of the debt queue
sump: debt auction bid size, i.e. the fixed debt quantity to be covered by any one debt auction