Editing Coherence

{{Broad-concept article}}{{wiktionary|coherence|coherency|coherent|incoherence|incoherent}}

Coherence is, in general, a state or situation in which all the parts or ideas fit together well so that they form a united whole.

More specifically, '''coherence''', '''coherency''', or '''coherent''' may refer to the following:

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== Physics ==

* [[Coherence (physics)]], an ideal property of waves that enables stationary (i.e. temporally and spatially constant) interference
* [[Coherence (units of measurement)]], a derived unit that, for a given system of quantities and for a chosen set of base units, is a product of powers of base units with no other proportionality factor than one
* [[Coherence time]], the time over which a propagating wave (especially a laser or maser beam) may be considered coherent; the time interval within which its phase is, on average, predictable

== Mathematics ==

* [[Coherence (philosophical gambling strategy)]], a concept in Bayesian statistics
* [[Coherence (signal processing)]], a statistic that can be used to examine the relation between two signals or data sets
* [[Coherence (statistics)]], a property of self-consistency across a set of assessments, or  the strength of association between two series
* [[Coherence condition]] in category theory, a collection of conditions requiring that various compositions of elementary morphisms are equal
* [[Coherency (homotopy theory)]] in homotopy theory and (higher) category theory
* [[Coherent sampling]], a relationship used in Fast Fourier transforms
* [[Coherent set of characters]] in representation theory, a property of sets of characters that allows one to extend an isometry from the degree-zero subspace of a space of characters to the whole space
* [[Coherent sheaf]], a specific class of sheaves having particularly manageable properties closely linked to the geometrical properties of the underlying space
* [[Mutual coherence (linear algebra)]], sometimes referred to as coherence,  the maximum absolute value of the cross-correlations between the columns of a matrix
* [[Multi-spectral phase coherence]], a generalized nonlinear cross-frequency phase coupling metric introduced by Yang et al., 2016
* [[Coherence (fairness)]], a consistency requirement of fair division rules.
* [[Coherent topology]], topology determined by a family of subspaces.

== Philosophy ==

* [[Coherentism]], philosophical theories in modern epistemology, the study of knowledge
* [[Coherence theory of truth]], a theory which regards truth as coherence within some specified set of sentences, propositions or beliefs

== Computer science ==
* [[Coherence (programming language)]], an experimental programming language based upon Subtext
* [[Cache coherence]], a special case of memory coherence
* [[Memory coherence]], a concept in computer architecture
* In scrum and agile methodologies, [[Product backlog#Coherence|coherence]] is defined as a measure of the relationships between backlog items which make them worthy of consideration as a whole.

=== IT products ===
* [[Coherence (software)]], a component of Parallels Desktop for Mac, the Windows virtualization software
* [[Coherent (operating system)]], a UNIX-clone operating system
* [[Oracle Coherence]], an in-memory data grid product from Oracle

== Other uses ==

* [[Coherence (cognitive science)]], a property of mental/cognitive states
* [[Coherence (linguistics)]], what makes a text semantically meaningful
* [[Coherence (music theory)]], a synonym for strict Rothenberg propriety in diatonic set theory
* [[Coherent optical module]], a hot-pluggable optical transceiver implementing a coherent modulation algorithm
* [[Coherence time (communications systems)]], duration when a communication channel can be assumed to be constant
* [[Coherent, Inc.]], a company specializing in equipment to make and measure coherent light (lasers)
* [[Coherent risk measure]] in  financial economics, a function that satisfies properties of monotonicity, sub-additivity, homogeneity, and translational invariance
* [[Coherence (film)|''Coherence'' (film)]], a 2013 science fiction film by James Ward Byrkit
* Sense of coherence, a construct in the health theory [[Salutogenesis#Sense of coherence (SOC)|salutogenesis]]
* [[Policy coherence for development]], a concept in development cooperation

== See also ==

* [[Cohesion (disambiguation)]]
* [[Mutual coherence (disambiguation)]]
* {{Lookfrom|coherence}}
* {{Lookfrom|coherent}}

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