What I think I learned from Calvo (2010)
What I think I learned from Calvo (2010) includes two points. First, I can think this problem in relative-price framework. Or, is it fruitful to think this problem in general-price framework? Second, liquidity stock might be the one we can make use of. Usual money stock might not be relevant. So-called non-performing asset problem could be reformulated as the situation in which non-monetary assets don't create liquidity enough. This could be a case of negative externality.