Invariant and invariance may refer to:
Computer science
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Invariant (computer science)
In mathematics, an invariant is a property of a mathematical object (or a class of mathematical objects) which remains unchanged after operations or transformations of a certain type are applied to the objects. The particular class of object ...
, an expression whose value doesn't change during program execution
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Loop invariant
In computer science, a loop invariant is a property of a program loop that is true before (and after) each iteration. It is a logical assertion, sometimes checked within the code by an assertion call. Knowing its invariant(s) is essential in ...
, a property of a program loop that is true before (and after) each iteration
* A data type in method overriding that is neither
covariant nor contravariant
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Class invariant
In computer programming, specifically object-oriented programming, a class invariant (or type invariant) is an invariant used for constraining objects of a class. Methods of the class should preserve the invariant. The class invariant constr ...
, an invariant used to constrain objects of a class
Physics, mathematics, and statistics
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Invariant (mathematics)
In mathematics, an invariant is a property of a mathematical object (or a class of mathematical objects) which remains unchanged after operations or transformations of a certain type are applied to the objects. The particular class of object ...
, a property of a mathematical object that is not changed by a specific operation or transformation
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Rotational invariance In mathematics, a function defined on an inner product space is said to have rotational invariance if its value does not change when arbitrary rotations are applied to its argument.
Mathematics
Functions
For example, the function
:f(x,y) = ...
, the property of function whose value does not change when arbitrary rotations are applied to its argument
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Scale invariance
In physics, mathematics and statistics, scale invariance is a feature of objects or laws that do not change if scales of length, energy, or other variables, are multiplied by a common factor, and thus represent a universality.
The technical te ...
, a property of objects or laws that do not change if scales of length, energy, or other variables, are multiplied by a common factor
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Topological invariant
In topology and related areas of mathematics, a topological property or topological invariant is a property of a topological space that is invariant under homeomorphisms. Alternatively, a topological property is a proper class of topological spac ...
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Invariant (physics) In theoretical physics, an invariant is an observable of a physical system which remains unchanged under some transformation. Invariance, as a broader term, also applies to the no change of form of physical laws under a transformation, and is clo ...
, something does not change under a transformation, such as from one reference frame to another
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Invariant estimator
In statistics, the concept of being an invariant estimator is a criterion that can be used to compare the properties of different estimators for the same quantity. It is a way of formalising the idea that an estimator should have certain intuitive ...
in statistics
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Measurement invariance, a statistical property of measurement
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Oxford University Invariant Society
The Oxford University Invariant Society, or 'The Invariants', is a university society open to members of the University of Oxford, dedicated to promotion of interest in mathematics. The society regularly hosts talks from professional mathemati ...
, an Oxford student mathematics club
Other uses
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Invariant (linguistics)
In linguistic morphology, inflection (or inflexion) is a process of word formation in which a word is modified to express different grammatical categories such as tense, case, voice, aspect, person, number, gender, mood, animacy, and defini ...
, a word that does not undergo inflection
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Invariant (music)
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Writer invariant Writer invariant, also called authorial invariant or author's invariant, is a property of a text which is invariant of its author, that is, it will be similar in all texts of a given author and different in texts of different authors. It can be used ...
, property of a text which is similar in all texts of a given author, and different in texts of different authors
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''Invariance'' (magazine), a French Communist journal
* ''
Invariances'', a 2001 book by philosopher Robert Nozick
See also
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{{Disambiguation