These systems involve explicit rules about what people can use, what their responsibilities are, and how they will be punished if they break the rules.

ECONOMIST: Economics focus

There is an implicit covenant between the NFL and its fans that the games are fair, that they are played based on a set of explicit rules, that there is a level playing field and that there is, at least with 15:00 on the clock before the first quarter, a chance that either team on the field can win the game.

FORBES: Using Replacement Refs Would Be A Disaster For The NFL

But the voting rules are explicit.

FORBES: Craig Biggio, Mike Piazza, Fred McGriff And Lee Smith Deserve Induction Into Baseball's Hall

Today they enjoy laxer accounting, loose collateral rules at central banks, explicit debt guarantees and asset-purchasing schemes.

ECONOMIST: Bank bonuses

One can also expect any such approval to be conditioned upon the explicit permission of judicial enforcement of said rules.

FORBES: How To Make Sure Your Company's Data Doesn't Get Stuck In Europe

The Italian case is of particular interest, because it suggests that sometimes rules may be written with the explicit purpose of circumventing them.

FORBES: Are European Fiscal Rules a Greek Farce?

The key issue, therefore, relates to an independent Scotland's membership of the EU. As outlined, an independent Scottish state could not automatically become a new member of the EU upon independence because there is no explicit provision for this process in the EU's own membership rules.

BBC: Scotland politics