Ask the knowledge emperor to answer a question about economics.

There is nothing wrong: A owes B $1, B owes C $1 and C owes A $1. Generally speaking, neither of them owes anyone, which is essentially a triangular debt problem. The joke means: in fact, if you save one of them, then everyone will live. If you don't save him, his family will not die. Therefore, when there is a lack of liquidity, the central bank or commercial banks often provide liquidity urgently to avoid this situation that the original enterprise is well managed and is simply dragged to death by others, thus avoiding systemic risks. This situation is particularly common in times of economic crisis. The essence of the central bank's 4 trillion yuan is to play the role of the owner.