Editing Reduction (section)

== Science and technology ==
=== Chemistry ===
* [[Reduction (chemistry)]], part of a reduction-oxidation (redox) reaction in which atoms have their oxidation state changed.
** [[Organic redox reaction]], a redox reaction that takes place with organic compounds
** Ore reduction: see [[smelting]]

=== Computing and algorithms ===
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* [[Reduction (complexity)]], a transformation of one problem into another problem
* [[Reduction (recursion theory)]], given sets A and B of natural numbers, is it possible to effectively convert a method for deciding membership in B into a method for deciding membership in A?
* [[Bit Rate Reduction]], an audio compression method
* [[Data reduction]], simplifying data in order to facilitate analysis
* [[Graph reduction]], an efficient version of non-strict evaluation
* [[L-reduction]], a transformation of optimization problems which keeps the approximability features
* [[Partial order reduction]], a technique for reducing the size of the state-space to be searched by a model checking algorithm
* [[Strength reduction]], a compiler optimization where a function of some systematically changing variable is calculated more efficiently by using previous values of the function
* [[Reduce (computer algebra system)]], a general-purpose computer algebra system geared towards applications in physics
* [[Reduce (higher-order function)]], in functional programming, a family of higher-order functions that process a data structure in some order and build up a return value
* [[Reduced instruction set computing]], a CPU design philosophy favoring an instruction set reduced in size and complexity of addressing, to simplify implementation, instruction level parallelism, and compiling

=== Pure mathematics and statistics ===
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* Reducible as the opposite of [[irreducible (mathematics)]]
* [[Reduction (mathematics)]], the rewriting of an expression into a simpler form
* [[Beta reduction]], the rewriting of an expression from lambda calculus into a simpler form
* [[Dimension reduction]], the process of reducing the number of random variables under consideration
* [[Lattice reduction]], given an integer lattice basis as input, to find a basis with short, nearly orthogonal vectors
* [[Subject reduction]] or preservation, a rewrite of an expression that does not change its type
* [[Reduction of order]], a technique for solving second-order ordinary differential equations
* [[Reduction of the structure group]], for a <math>G</math>-bundle <math>B</math> and a map <math>H \to G</math> an <math>H</math>-bundle <math>B_H</math> such that the pushout <math>B_H \times_H G</math> is isomorphic to <math>B</math>
* [[Reduction system]], reduction strategy, the application of rewriting systems to eliminate reducible expressions
* [[Reduced form]], in statistics, an equation which relates the endogenous variable X to all the available exogenous variables, both those included in the regression of interest (W) and the instruments (Z)
* [[Reduced homology]], a minor modification made to homology theory in algebraic topology, designed to make a point have all its homology groups zero
* [[Reduced product]], a construction that generalizes both direct product and ultraproduct
* [[Reduced residue system]], a set of φ(n) integers such that each integer is relatively prime to n and no two are congruent modulo n
* [[Reduced ring]], a ring with no non-zero nilpotent elements
* [[Reduced row echelon form]], a certain reduced row echelon form of a matrix which completely and uniquely determines its row space
* [[Reduced word]], in a free group, a word with no adjacent generator-inverse pairs
* [[Variance reduction]], a procedure used to increase the precision of the estimates that can be obtained for a given number of iterations

=== Medicine ===
==== Medical procedures ====
* [[Lung volume reduction surgery]], a treatment for chronic obstructive pulmonary disease
* [[Selective reduction]] (or fetal reduction), the practice of reducing the number of fetuses in a multifetal pregnancy
* [[Reduction (orthopedic surgery)]], a medical procedure to restore a fracture or dislocation to the correct alignment
* [[Ventricular reduction]], a type of operation in cardiac surgery
* Cosmetic surgery:
** [[Breast reduction]]
** [[Jaw reduction]]

==== Other uses in medicine ====
* [[Weight loss]]
* In epidemiology:
** [[Relative risk reduction]], the absolute risk reduction by the control event rate
** [[Absolute risk reduction]], the decrease in risk of a given activity or treatment in relation to a control activity or treatment
* [[Urea reduction ratio]] (URR),  a dimensionless number used to quantify hemodialysis treatment adequacy

=== Physics ===
* [[Dimensional reduction]], the limit of a compactified theory where the size of the compact dimension goes to zero
* [[Reduction criterion]], in quantum information theory, a necessary condition a mixed state must satisfy in order for it to be separable
* [[Reduced mass]], the "effective" inertial mass appearing in the two-body problem of Newtonian mechanics
* [[Reduced properties]] (pressure, temperature, or volume) of a fluid, defined based on the fluid's critical point

=== Other uses in science and technology ===
* [[Lithic reduction]], in Stone Age toolmaking, to detach lithic flakes from a lump of tool stone
* [[Noise reduction]], in acoustic or signal processing
* [[Reduction drive]], a mechanical device to shift rotational speed