"Closure" is a property which a set either has or lacks with respect to a given operation. A set is closed with respect to that operation if the operation can always be completed with elements in the set. For example, the set of even natural numbers,...

In mathematics, a set is said to be closed under some operation if the operation on members of the set produces a member of the set. For example, the real numbers are closed under subtraction, but the natural numbers are not: 3 and 7 are both natural...

We are likely to see more chemistry department closures as the only body that could conceivably prevent them is completely ineffective, according to a new UK Science and Technology Committee report. The Higher Education Funding Council for England (HEFCE) does not have 'the...

In the realm of mathematics, it's hard to imagine anything more basic than the counting numbers: 1, 2, 3, and so on. Yet this set of mathematical objects abounds with beautiful and unexpected patterns. For example, pick any number and double it. You'll...

Historic Tempelhof Airport — which played a key role in the Berlin airlift in the wake of World War II — will close to passengers in 2008, Germany's top administrative court confirmed Tuesday.The court threw out a bid to prevent Tempelhof's closure as part of...

Closing U.S. borders would be the last option in combating the spread of bird flu, a senior State Department official said Monday. It would not be likely to decrease the number of cases, would interrupt essential services and would disrupt...