From 47d9f2aa03280aaa11f8d7aaa8b3efb0740096c5 Mon Sep 17 00:00:00 2001
From: Marina Anagnostopoulou-Merkouri <mam49@st-andrews.ac.uk>
Date: Wed, 11 Nov 2020 15:26:47 +0000
Subject: [PATCH] documentation

---
 doc/oper.xml    | 32 ++++++++++++++++++++++++++++++++
 doc/z-chap4.xml |  1 +
 2 files changed, 33 insertions(+)

diff --git a/doc/oper.xml b/doc/oper.xml
index 6b5398e6f..6d257ca08 100644
--- a/doc/oper.xml
+++ b/doc/oper.xml
@@ -1570,6 +1570,38 @@ gap> DigraphShortestDistance(D, [1, 3], [3, 5]);
 </ManSection>
 <#/GAPDoc>
 
+<#GapDoc Label= "Dominators2">
+<ManSection>
+  <Oper Name="Dominators2"
+      Arg="digraph, root"
+  <Returns>A list of lists </Returns>
+    <Description>
+    Dominators2 is a function that takes a <A>digraph</A> and a specific root
+    <A>vertex</A> and returns the dominators of each vertex with respect to
+    the root. The root must be a verex of the digraph. The algorithm is an 
+    implementation of the fast algorith written by Thomas Lengauer and Robert 
+    Endre Tarjan. If there is no path from the root to a specific vertex, 
+    the output will contain a hole in the corresponding position.
+    <Example><! [CDATA[
+gap> d := Digraph([[2], [3, 6], [2, 4], [1], [], [3]]);
+<immutable digraph with 6 vertices, 7 edges>
+gap> Dominators2(d, 1);
+[ [ 1 ], [ 2, 1 ], [ 3, 2, 1 ], [ 4, 3, 2, 1 ],, [ 6, 2, 1 ] ]
+gap> Dominators2(d, 2);
+[ [ 1, 4, 3, 2 ], [ 2 ], [ 3, 2 ], [ 4, 3, 2 ],, [ 6, 2 ] ]
+gap> Dominators2(d, 3);
+[ [ 1, 4, 3 ], [ 2, 3 ], [ 3 ], [ 4, 3 ],, [ 6, 2, 3 ] ]
+gap> Dominators2(d, 4);
+[ [ 1, 4 ], [ 2, 1, 4 ], [ 3, 2, 1, 4 ], [ 4 ],, [ 6, 2, 1, 4 ] ]
+gap> Dominators2(d, 5);
+[ ,,,, [ 5 ] ]
+gap> Dominators2(d, 6);
+[ [ 1, 4, 3, 6 ], [ 2, 3, 6 ], [ 3, 6 ], [ 4, 3, 6 ],, [ 6 ] ]
+]]></Example>
+  </Description>
+</ManSection>
+<#/GAPDoc>
+
 <#GAPDoc Label="PartialOrderDigraphMeetOfVertices">
 <ManSection>
   <Oper Name="PartialOrderDigraphMeetOfVertices"
diff --git a/doc/z-chap4.xml b/doc/z-chap4.xml
index 447edfb14..43ee7ad39 100644
--- a/doc/z-chap4.xml
+++ b/doc/z-chap4.xml
@@ -62,6 +62,7 @@
     <#Include Label="IsReachable">
     <#Include Label="DigraphPath">
     <#Include Label="DigraphShortestPath">
+    <#Include Label="Dominators2">
     <#Include Label="IteratorOfPaths">
     <#Include Label="DigraphAllSimpleCircuits">
     <#Include Label="DigraphLongestSimpleCircuit">