Русско-англо-русский юридический словарь

A natural monopoly is a monopoly in an industry in which it is most efficient (involving the lowest long-run average cost) for production to be concentrated in a single firm. This market situation gives the largest supplier in an industry, often the first supplier in a market, an overwhelming cost advantage over other actual and potential competitors, so a natural monopoly situation generally leads to an actual monopoly. (Wikipedia)

An employment record book is an official personal document recording the employment status of its owner over time. Many European countries issue such documents. The first employment record books are said to have been issued in German Reich in 1892 in the mining industry. (Wikipedia)

In contract law, we can sort the rules into two sorts, "default rules" and "mandatory rules."

Here's an example. The Uniform Commercial Code (or UCC, the codified law of contract that applies to contracts between businesses as a matter of state law in the United States) creates a duty to act in good faith--this is a mandatory rule, because this duty cannot be disclaimed by a contractual provision. The UCC also includes an implied "warranty of merchantability," that attaches to contracts, but can be waived by agreement--this is a default rule.

Grasping this distinction is important for at least two reasons. First, unless you know whether a given rule of contract law is a default rule or a mandatory rule, you don't really know the law. And it isn't always clear whether a given rule is one or the other: the usual tipoff is language like, "unless the contract provides otherwise" or "absent an agreement to the contrary." (Legal Theory Lexicon 050: Default Rules and Completeness)

In contract law, we can sort the rules into two sorts, "default rules" and "mandatory rules."

Here's an example. The Uniform Commercial Code (or UCC, the codified law of contract that applies to contracts between businesses as a matter of state law in the United States) creates a duty to act in good faith--this is a mandatory rule, because this duty cannot be disclaimed by a contractual provision. The UCC also includes an implied "warranty of merchantability," that attaches to contracts, but can be waived by agreement--this is a default rule.

Grasping this distinction is important for at least two reasons. First, unless you know whether a given rule of contract law is a default rule or a mandatory rule, you don't really know the law. And it isn't always clear whether a given rule is one or the other: the usual tipoff is language like, "unless the contract provides otherwise" or "absent an agreement to the contrary." (Legal Theory Lexicon 050: Default Rules and Completeness)