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In [[mathematics]], an '''alternating sign matrix''' is a [[square matrix]] of 0s, 1s, and −1s such that the sum of each row and column is 1 and the nonzero entries in each row and column alternate in sign. These matrices generalize [[Permutation matrix|permutation matrices]] and arise naturally when using [[Dodgson condensation]] to compute a determinant.
| last = Hone | first = Andrew N. W.
| doi = 10.1098/rsta.2006.1887
| issue = 1849
| journal = Philosophical Transactions of the Royal Society of London
| mr = 2317901
| pages = 3183–3198
| title = Dodgson condensation, alternating signs and square ice
| volume = 364
| year = 2006| bibcode = 2006RSPTA.364.3183H
}}</ref> They are also closely related to the [[six-vertex model]] with ___domain wall boundary conditions from [[statistical mechanics]]. They were first defined by William Mills, [[David P. Robbins|David Robbins]], and Howard Rumsey in the former context.
==
An example of an alternating sign matrix (that is not also a permutation matrix) is▼
A [[permutation matrix]] is an alternating sign matrix, and an alternating sign matrix is a permutation matrix if and only if no entry equals {{math|−1}}.
[[File:Matrice signes alternants 4x4.svg|thumbnail|Puzzle picture]]▼
▲[[File:Matrice signes alternants 4x4.svg|thumbnail|Puzzle picture]]
:<math>
\begin{bmatrix}
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:1, 1, 2, 7, 42, 429, 7436, 218348, … {{OEIS|id=A005130}}.
This theorem was first proved by [[Doron Zeilberger]] in 1992.<ref>Zeilberger, Doron, [http://www.combinatorics.org/Volume_3/Abstracts/v3i2r13.html "Proof of the alternating sign matrix conjecture"], ''[http://www.combinatorics.org/ Electronic Journal of Combinatorics]'' 3 (1996), R13.</ref> In 1995, [[Greg Kuperberg]] gave a short proof<ref>[[Greg Kuperberg|Kuperberg, Greg]], [http://
==Razumov–Stroganov problem==
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==Further reading==
* [[David Bressoud|Bressoud, David M.]], ''Proofs and Confirmations: The Story of the Alternating Sign Matrix Conjecture'', MAA Spectrum, Mathematical Associations of America, Washington, D.C., 1999.{{ISBN|978-0521666466}}
* [[David Bressoud|Bressoud, David M.]] and Propp, James, [
* Mills, William H., [[David P. Robbins|Robbins, David P.]], and Rumsey, Howard Jr., Proof of the Macdonald conjecture, ''Inventiones Mathematicae'', 66 (1982), 73–87.
* Mills, William H., [[David P. Robbins|Robbins, David P.]], and Rumsey, Howard Jr., Alternating sign matrices and descending plane partitions, ''Journal of Combinatorial Theory, Series A'', 34 (1983), 340–359.
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{{Matrix classes}}
[[Category:Matrices (mathematics)]]
[[Category:Enumerative combinatorics]]
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