Reductions

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 * Reductions** (as opposed to pruning) are a class of search heuristics that decrease the depth to which a certain branch of the tree is searched, also interpreted as negative extension

=Recursive Reductions=
 * Late Move Reductions - LMR
 * Fail-High Reductions - FHR
 * Null Move Reductions

=Near the Tips=
 * Razoring

=Pruning after a reduced Search= Some dynamic pruning techniques base their pruning decision on a reduced search by factor R, also applied recursively:
 * Null Move Pruning
 * Multi-Cut

A none recursive pruning based on reduction at some fixed depth is applied by:
 * ProbCut

=See also=
 * Pruning
 * Extensions

=Forum Posts=

1998 ...

 * [|A new selective heuristic?] by Frank Schneider, CCC, June 21, 1998

2000 ...

 * [|Evaluation-based Reductions and/or Extensions] by Tom Likens, CCC, December 28, 2003 » Extensions
 * [|extensions + reductions + pruning = confusion] by Johan de Koning, CCC, March 24, 2004 (was [|Shredder 8 secret: search depth?])

2005 ...

 * [|Reductions and null move refutations] by Tord Romstad, Winboard Forum, April 18, 2005 » Null Move Pruning
 * [|Has anyone tested Gambit Fruit with Rebel Reductions on?] by Ryan B., CCC, November 15, 2005 » Rebel, Gambit Fruit
 * [|Reducing King Moves?] by mjlef, Winboard Forum, January 03, 2007
 * [|Toga/Glaurung/Strelka Prunings/Reductions] by Edsel Apostol, CCC, January 31, 2008 » Toga, Glaurung, Strelka, Pruning

2010 ...

 * [|Reducing/Pruning Bad Captures (SEE < 0)] by Edsel Apostol, CCC, August 19, 2011 » SEE
 * [|Reductions from internal iterative deepening] by Evert Glebbeek, CCC, August 20, 2012 » Internal Iterative Deepening
 * [|Houdini 3 reducing the depth feature] by Maurizio Maglio, CCC, October 17, 2012 » Houdini
 * [|Pruning in PV nodes] by Sergei S. Markoff, CCC, January 14, 2014 » Root, Node Types
 * [|variable reductions] by Robert Hyatt, CCC, June 22, 2014

2015 ...

 * [|Ratio reduction] by Steven Edwards, CCC, September 20, 2015 » Late Move Reductions, Symbolic
 * [|Reduction Research Question] by Dennis Sceviour, CCC, September 25, 2015
 * [|Reductions] by Harm Geert Muller, CCC, May 22, 2016
 * [|EMR & EMP] by Michael Sherwin, CCC, July 19, 2016
 * [|Floating Move Reduction] by Dennis Sceviour, CCC, September 14, 2016
 * [|EMR based on Null Move threat] by Michael Sherwin, CCC, October 30, 2017

=External Links=
 * [|Reduction (disambiguation) from Wikipedia]
 * [|Programmer Corner - How Rebel Plays Chess - Reductions] by Ed Schröder, [|pdf reprint]

=References= =What links here?= include page="Reductions" component="backlinks" limit="100"
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