Editing No-trade theorem (section)

==Informal explanation==
The idea behind the proof of the no-trade theorem is that if there is common knowledge about the structure of a market, then any bid or offer (i.e. attempt to initiate a trade) will reveal the bidder's private knowledge and will be incorporated into [[market price]]s even before anyone accepts the bid or offer, so no profit will result. Another way to put it is: all the traders in the market are rational, and thus they know that all the prices are rational/efficient; therefore, anyone who makes an offer to them must have special knowledge, else why would they be making the offer? Accepting the offer would [[Adverse_selection|make them a loser]]. All the traders will reason the same way, and thus will not accept any offers.