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		<title>imported&gt;Headbomb: ce</title>
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		<summary type="html">&lt;p&gt;ce&lt;/p&gt;
&lt;p&gt;&lt;b&gt;New page&lt;/b&gt;&lt;/p&gt;&lt;div&gt;{{about|the mathematical concept of Graph Algebras|&amp;quot;Graph Algebra&amp;quot; as used in the social sciences|Graph algebra (social sciences)}}&lt;br /&gt;
{{Use shortened footnotes|date=May 2021}}&lt;br /&gt;
&lt;br /&gt;
In [[mathematics]], especially in the fields of [[universal algebra]] and [[graph theory]], a &amp;#039;&amp;#039;&amp;#039;graph algebra&amp;#039;&amp;#039;&amp;#039; is a way of giving a [[directed graph]] an [[algebraic structure]].  It was introduced by McNulty and Shallon,{{sfn|McNulty|Shallon|1983|loc=[https://archive.org/details/universalalgebra0000unse/page/206 pp. 206–231]}} and has seen many uses in the field of universal algebra since then.&lt;br /&gt;
&lt;br /&gt;
== Definition ==&lt;br /&gt;
Let {{math|1=&amp;#039;&amp;#039;D&amp;#039;&amp;#039; = (&amp;#039;&amp;#039;V&amp;#039;&amp;#039;, &amp;#039;&amp;#039;E&amp;#039;&amp;#039;)}} be a directed [[graph (data structure)|graph]], and {{math|0}} an element not in {{mvar|V}}. The graph algebra associated with {{mvar|D}} has underlying set &amp;lt;math&amp;gt;V \cup \{0\}&amp;lt;/math&amp;gt;, and is equipped with a multiplication defined by the rules&lt;br /&gt;
* {{math|1=&amp;#039;&amp;#039;xy&amp;#039;&amp;#039; = &amp;#039;&amp;#039;x&amp;#039;&amp;#039;}} if &amp;lt;math&amp;gt;x,y \in V&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;(x,y) \in E&amp;lt;/math&amp;gt;,&lt;br /&gt;
* {{math|1=&amp;#039;&amp;#039;xy&amp;#039;&amp;#039; = 0}} if &amp;lt;math&amp;gt;x,y \in V \cup \{0\}&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;(x,y)\notin E&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
== Applications ==&lt;br /&gt;
This notion has made it possible to use the methods of graph theory in universal algebra and several other areas of [[discrete mathematics]] and [[computer science]]. Graph algebras have been used, for example, in constructions concerning [[Dual (category theory)|dualities]],{{sfn|Davey|Idziak|Lampe|McNulty|2000|pp=145–172}} [[equational theory|equational theories]],{{sfn|Pöschel|1989|pp=273–282}} [[flatness (systems theory)|flatness]],{{sfn|Delić|2001|pp=453–469}} [[groupoid (algebra)|groupoid]] [[ring (mathematics)|rings]],{{sfn|Lee|1991|pp=117–121}} [[topology|topologies]],{{sfn|Lee|1988|pp=147–156}} [[variety (universal algebra)|varieties]],{{sfn|Oates-Williams|1984|pp=175–177}}  [[finite-state machine]]s,{{sfn|Kelarev|Miller|Sokratova|2005|pp=46–54}}{{sfn|Kelarev|Sokratova|2003|pp=31–43}}&lt;br /&gt;
tree languages and [[tree automata]],{{sfn|Kelarev|Sokratova|2001|pp=305–311}} etc.&lt;br /&gt;
&lt;br /&gt;
== See also ==&lt;br /&gt;
* [[Group algebra (disambiguation)]]&lt;br /&gt;
* [[Incidence algebra]]&lt;br /&gt;
* [[Path algebra]]&lt;br /&gt;
&lt;br /&gt;
==Citations==&lt;br /&gt;
{{Reflist|20em}}&lt;br /&gt;
&lt;br /&gt;
==Works cited==&lt;br /&gt;
{{refbegin|35em}}&lt;br /&gt;
*{{Cite journal | title = Dualizability and graph algebras&lt;br /&gt;
 | last1 = Davey | first1 = Brian A.&lt;br /&gt;
 | last2 = Idziak | first2 = Pawel M.&lt;br /&gt;
 | last3 = Lampe | first3 = William A.&lt;br /&gt;
 | last4 = McNulty | first4 = George F.&lt;br /&gt;
 | journal = [[Discrete Mathematics (journal)|Discrete Mathematics]]&lt;br /&gt;
 | year = 2000 | volume = 214 | issue = 1 | pages = 145–172&lt;br /&gt;
 | doi = 10.1016/S0012-365X(99)00225-3 | issn = 0012-365X | mr = 1743633&lt;br /&gt;
| doi-access = free }}&lt;br /&gt;
*{{Cite journal | title = Finite bases for flat graph algebras&lt;br /&gt;
 | last = Delić | first = Dejan&lt;br /&gt;
 | journal = [[Journal of Algebra]]&lt;br /&gt;
 | year = 2001 | volume = 246 | issue = 1 | pages = 453–469&lt;br /&gt;
 | doi = 10.1006/jabr.2001.8947 | issn = 0021-8693 | mr = 1872631&lt;br /&gt;
 | doi-access = free&lt;br /&gt;
}}&lt;br /&gt;
*{{Cite journal | title = Languages recognized by two-sided automata of graphs&lt;br /&gt;
 | last1 = Kelarev | first1 = A.V.&lt;br /&gt;
 | last2 = Miller | first2 = M.&lt;br /&gt;
 | last3 = Sokratova | first3 = O.V.&lt;br /&gt;
 | journal = Proc. Estonian Akademy of Science&lt;br /&gt;
 | year = 2005 | volume = 54 | issue = 1 | pages = 46–54&lt;br /&gt;
 | issn = 1736-6046 | mr = 2126358&lt;br /&gt;
}}&lt;br /&gt;
*{{Cite journal | title = Directed graphs and syntactic algebras of tree languages&lt;br /&gt;
 | last1 = Kelarev | first1 = A.V.&lt;br /&gt;
 | last2 = Sokratova | first2 = O.V.&lt;br /&gt;
 | journal = J. Automata, Languages &amp;amp; Combinatorics&lt;br /&gt;
 | year = 2001 | volume = 6 | issue = 3 | pages = 305–311&lt;br /&gt;
 | issn = 1430-189X | mr = 1879773&lt;br /&gt;
}}&lt;br /&gt;
*{{Cite journal | title = On congruences of automata defined by directed graphs&lt;br /&gt;
 | last1 = Kelarev | first1 = A.V.&lt;br /&gt;
 | last2 = Sokratova | first2 = O.V.&lt;br /&gt;
 | journal = Theoretical Computer Science&lt;br /&gt;
 | year = 2003 | volume = 301 | issue = 1–3 | pages = 31–43&lt;br /&gt;
 | url = https://eprints.utas.edu.au/157/1/congruences.pdf&lt;br /&gt;
 | doi = 10.1016/S0304-3975(02)00544-3 | issn = 0304-3975 | mr = 1975219&lt;br /&gt;
}}&lt;br /&gt;
*{{Cite journal | title = Graph algebras which admit only discrete topologies&lt;br /&gt;
 | last = Lee | first = S.-M.&lt;br /&gt;
 | journal = Congr. Numer&lt;br /&gt;
 | year = 1988 | volume = 64 | pages = 147–156&lt;br /&gt;
 | issn = 1736-6046 | mr = 0988675&lt;br /&gt;
}}&lt;br /&gt;
*{{Cite journal | title = Simple graph algebras and simple rings&lt;br /&gt;
 | last = Lee | first = S.-M.&lt;br /&gt;
 | journal = Southeast Asian Bull. Math&lt;br /&gt;
 | year = 1991 | volume = 15 | issue = 2 | pages = 117–121&lt;br /&gt;
 | issn = 0129-2021 | mr = 1145431&lt;br /&gt;
}}&lt;br /&gt;
*{{Cite book| chapter = Inherently nonfinitely based finite algebras&lt;br /&gt;
 | last1 = McNulty | first1 = George F.&lt;br /&gt;
 | last2 = Shallon | first2 = Caroline R.&lt;br /&gt;
 | year = 1983&lt;br /&gt;
 | title = Universal algebra and lattice theory (Puebla, 1982)&lt;br /&gt;
 | editor1-last = Freese | editor1-first = Ralph S.&lt;br /&gt;
 | editor2-last = Garcia | editor2-first = Octavio C.&lt;br /&gt;
 | publisher = [[Springer-Verlag]] | location = Berlin, New York City&lt;br /&gt;
 | volume = 1004 | series = Lecture Notes in Math.&lt;br /&gt;
 | at = [https://archive.org/details/universalalgebra0000unse/page/206 pp. 206–231]&lt;br /&gt;
 | url = https://archive.org/details/universalalgebra0000unse | via = [[Internet Archive]]&lt;br /&gt;
 | doi = 10.1007/BFb0063439 | hdl = 10338.dmlcz/102157 | isbn = 978-354012329-3 | mr = 716184&lt;br /&gt;
 | hdl-access = free&lt;br /&gt;
}}&lt;br /&gt;
*{{Cite journal | title = On the variety generated by Murskiĭ&amp;#039;s algebra&lt;br /&gt;
 | last = Oates-Williams | first = Sheila&lt;br /&gt;
 | author-link = Sheila Oates Williams&lt;br /&gt;
 | journal = [[Algebra Universalis]]&lt;br /&gt;
 | year = 1984 | volume = 18 | issue = 2 | pages = 175–177&lt;br /&gt;
 | doi = 10.1007/BF01198526 | issn = 0002-5240 | mr = 743465 | s2cid = 121598599&lt;br /&gt;
}}&lt;br /&gt;
*{{Cite journal | title = The equational logic for graph algebras&lt;br /&gt;
 | last = Pöschel | first = R.&lt;br /&gt;
 | journal = Z. Math. Logik Grundlag. Math.&lt;br /&gt;
 | year = 1989 | volume = 35 | issue = 3 | pages = 273–282&lt;br /&gt;
 | doi = 10.1002/malq.19890350311 | mr = 1000970&lt;br /&gt;
}}&lt;br /&gt;
{{refend}}&lt;br /&gt;
&lt;br /&gt;
==Further reading==&lt;br /&gt;
{{refbegin}}&lt;br /&gt;
*{{Cite book| title = Graph Algebras and Automata&lt;br /&gt;
 | last = Kelarev | first = A.V. | year = 2003&lt;br /&gt;
 | publisher = [[Marcel Dekker]] | place = New York City&lt;br /&gt;
 | url = https://archive.org/details/graphalgebrasaut0000kela | url-access = registration | via = [[Internet Archive]]&lt;br /&gt;
 | isbn = 0-8247-4708-9 | mr = 2064147&lt;br /&gt;
 | ref = none&lt;br /&gt;
}}&lt;br /&gt;
*{{cite journal | title = Subvarieties of varieties generated by graph algebras&lt;br /&gt;
 | last1 = Kiss | first1 = E.W.&lt;br /&gt;
 | last2 = Pöschel | first2 = R.&lt;br /&gt;
 | last3 = Pröhle | first3 = P.&lt;br /&gt;
 | journal = Acta Sci. Math.&lt;br /&gt;
 | year = 1990 | volume = 54 | issue = 1–2 | pages = 57–75&lt;br /&gt;
 | mr = 1073419&lt;br /&gt;
 | ref = none&lt;br /&gt;
}}&lt;br /&gt;
*{{Cite book| title = Graph algebras&lt;br /&gt;
 | last = Raeburn | first = Iain | year = 2005&lt;br /&gt;
 | publisher = [[American Mathematical Society]]&lt;br /&gt;
 | isbn = 978-082183660-6&lt;br /&gt;
 | ref = none&lt;br /&gt;
}}&lt;br /&gt;
{{refend}}&lt;br /&gt;
&lt;br /&gt;
[[Category:Graph theory]]&lt;br /&gt;
[[Category:Universal algebra]]&lt;/div&gt;</summary>
		<author><name>imported&gt;Headbomb</name></author>
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