Thanks for your answer.

> I'm not sure what happens in terms of formal default if a borrower deliberately and aggressively inlfates away its debt faster than lenders can react by demanding higher interest rates at the next auction.

This is the reason why I asked my question(s). Why would the borrower ever aggressively inflate away its debt, as opposed to gradually inflating it away? If there is no definite point of default, the US is either defaulting frequently, or can never default.

I wonder what the definition of default is, and if it's an event or a process.