From 8744a616df40d295eb9542d89106c32f018b8ae0 Mon Sep 17 00:00:00 2001
From: Joseph Edwards <josephdavidedwards@gmail.com>
Date: Tue, 27 Aug 2024 13:01:18 +0100
Subject: [PATCH] Add MeetBlist

---
 doc/ref/blist.xml |  1 +
 lib/list.g        | 28 ++++++++++++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/doc/ref/blist.xml b/doc/ref/blist.xml
index 79f780b687..f0e0210455 100644
--- a/doc/ref/blist.xml
+++ b/doc/ref/blist.xml
@@ -56,6 +56,7 @@ In function names we call boolean lists <E>blists</E> for brevity.
 <#Include Label="UniteBlistList">
 <#Include Label="IntersectBlist">
 <#Include Label="SubtractBlist">
+<#Include Label="MeetBlist">
 <#Include Label="FlipBlist">
 <#Include Label="SetAllBlist">
 <#Include Label="ClearAllBlist">
diff --git a/lib/list.g b/lib/list.g
index 33866ac617..5f132bad75 100644
--- a/lib/list.g
+++ b/lib/list.g
@@ -881,6 +881,34 @@ DeclareSynonym( "IntersectBlist", INTER_BLIST );
 ##
 DeclareSynonym( "SubtractBlist", SUBTR_BLIST );
 
+#############################################################################
+##
+#F  MeetBlist( <blist1>, <blist2> )
+##
+##  <#GAPDoc Label="MeetBlist">
+##  <ManSection>
+##  <Func Name="MeetBlist" Arg='blist1, blist2'/>
+##
+##  <Description>
+##  Returns true if <A>blist1</A> and <A>blist2</A> have <K>true</K> in the same
+##  position and <K>false</K> otherwise. It is equivalent to, but faster than
+##  <C>SizeBlist(IntersectionBlist(blist1, blist2)) &lt;&gt; 0</C>.
+##  The lists must have the same length.
+##  <Example><![CDATA[
+##  gap> blist1 := [ true, true, true, true ];;
+##  gap> blist2 := [ true, false, true, false ];;
+##  gap> MeetBlist( blist1, blist2 );
+##  true
+##  gap> FlipBlist( blist1 );
+##  gap> MeetBlist( blist1, blist2 );
+##  false
+##  ]]></Example>
+##  </Description>
+##  </ManSection>
+##  <#/GAPDoc>
+##
+DeclareSynonym( "MeetBlist", MEET_BLIST );
+
 #############################################################################
 ##
 #F  FlipBlist( <blist> )