# closure

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## closure

1. Politics (in a deliberative body) a procedure by which debate may be halted and an immediate vote taken
2. Geology the vertical distance between the crest of an anticline and the lowest contour that surrounds it
3. Logic the closed sentence formed from a given open sentence by prefixing universal or existential quantifiers to bind all its free variables
4. Maths the smallest closed set containing a given set
5. Psychol the tendency, first noted by Gestalt psychologists, to see an incomplete figure like a circle with a gap in it as more complete than it is

## closure

[′klō·zhər]
(civil engineering)
(geology)
The vertical distance between the highest and lowest point on an anticline which is enclosed by contour lines.
(mathematics)
The union of a set and its cluster points; the smallest closed set containing the set.
Property of a mathematical set such that a specified mathematical operation that is applied to elements of the set produces only elements of the same set

## closure

(programming)
In a reduction system, a closure is a data structure that holds an expression and an environment of variable bindings in which that expression is to be evaluated. The variables may be local or global. Closures are used to represent unevaluated expressions when implementing functional programming languages with lazy evaluation. In a real implementation, both expression and environment are represented by pointers.

A suspension is a closure which includes a flag to say whether or not it has been evaluated. The term "thunk" has come to be synonymous with "closure" but originated outside functional programming.

## closure

(theory)
In domain theory, given a partially ordered set, D and a subset, X of D, the upward closure of X in D is the union over all x in X of the sets of all d in D such that x <= d. Thus the upward closure of X in D contains the elements of X and any greater element of D. A set is "upward closed" if it is the same as its upward closure, i.e. any d greater than an element is also an element. The downward closure (or "left closure") is similar but with d <= x. A downward closed set is one for which any d less than an element is also an element.

("<=" is written in LaTeX as \subseteq and the upward closure of X in D is written \uparrow_\D X).
References in periodicals archive ?
The report firstly introduced the Sternal Closure Systems basics: definitions, classifications, applications and market overview; product specifications; manufacturing processes; cost structures, raw materials and so on.
During the closure, one lane will be made available to motorists heading to NPE.
After release of device, detailed echocardiography was performed to confirm satisfactory closure of ASD (fig-1).
The primary aim of this retrospective study is to compare the cosmetic outcomes of the circumferential purse-string approximation technique and conventional linear sutured closure of the skin following loop ileostomy closure.
Wirral Council served a closure order on the property at 52, Wright Street, in Wallasey, after neighbours reported a catalogue of terrifying incidents - including groups threatening those inside and kicking and smashing windows.
The closure is useful for vitamin, mineral, and supplement products because of its child-resistant performance.
Asked if the closure would help increase the number of tourists in the future, 61 percent of the respondents said it would.
These guidelines provide a broad framework for expeditious completion of various processes and procedures for closure of CPSEs by laying down important milestones in the closure process along with timelines, outlining the responsibilities of the concerned Ministries in the process.
Global Plastic Caps & Closures Market, published 12/2017, with 239 pages, is available for \$4,900.
Its direct integration with Bentley's asset lifecycle information management solution allows the scheduling of operational, maintenance, and scheme activities, and provides, for the first time, all HE's asset managers with the ability to visualize every planned road closure on a map.
The court can extend the closure notice beyond 48 hours - without issuing a closure order - if it is satisfied that the venue is or will be associated with nuisance to the public.

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