AL Econ what is [Robinson Cruse econmy]?

Robinson Cruse economy - 魯賓遜經濟
Actually, this economy is never existed and it is just an assumption. Under this economy, only 1 man exist, he know all things (no transaction and information cost) and therefore no competition exist.
Therefore, we call it 1-man economy - no trading and no competition.

In Robinson Crusoe Economy, competition can not conceivably to be existed. Also, transaction cost is alos not exist that because no any institution and market.

*BUT, there may exist information cost

p.s:
你都出左好多條econ問題bor - -"