v1.69

Author: grahamknockillaree

PackageInfo.g

@@ -8,8 +8,8 @@ SetPackageInfo( rec(
 
   PackageName := "HAP",
   Subtitle  := "Homological Algebra Programming",
-  Version := "1.68",
-  Date    := "09/07/2025",
+  Version := "1.69",
+  Date    := "17/07/2025",
   License := "GPL-2.0-or-later",
 
   SourceRepository := rec(

README.md

@@ -32,12 +32,12 @@ Please send your bug reports to graham.ellis(at)nuigalway.ie .
 On a Linux machine with GAP (and optionally Polymake) installed, the HAP
 library can be loaded as follows:
 
-* First download the file hap1.68.tar.gz to the subdirectory "pkg/" of GAP. (If
+* First download the file hap1.69.tar.gz to the subdirectory "pkg/" of GAP. (If
 you don't have access to this, then create a directory "pkg" in your home
 directory and download the file there.)
 
-* Change to directory "pkg/" and type "gunzip hap1.68.tar.gz" followed by
-"tar -xvf hap1.68.tar" .
+* Change to directory "pkg/" and type "gunzip hap1.69.tar.gz" followed by
+"tar -xvf hap1.69.tar" .
 
 * Start GAP. (If you have created "pkg" in your home directory then start GAP
 with the command "gap -l 'path/homedir;' "   where path/homedir is the path to
@@ -46,12 +46,12 @@ your home directory.)
 * In GAP type " LoadPackage("HAP"); " .
 
 * Help on HAP can be found on the HAP home page (a version of which is
-included in directory "pkg/Hap1.68/www" of this distribution).
+included in directory "pkg/Hap1.69/www" of this distribution).
 
 * Performance can be significantly improved by using a compiled version of the
 HAP library. A compiled version can be created by the following steps.
 
-1. Change to the directory "pkg/Hap1.68/" .
+1. Change to the directory "pkg/Hap1.69/" .
 2. Edit the file "compile" so that: PKGDIR is equal to the path to the
 directory "pkg" where your GAP packages are stored; GACDIR is equal to the
 path to the directory where the GAP compiler "gac" is stored.
@@ -60,4 +60,4 @@ path to the directory where the GAP compiler "gac" is stored.
 The next time HAP is loaded a compiled version will be loaded.
 
 * Should you want to return to an uncompiled version, change to the directory
-"pkg/Hap1.68/" and type "./uncompile".
+"pkg/Hap1.69/" and type "./uncompile".

date

@@ -1 +1 @@
-09 July 2025 
+17 July 2025 

doc/Undocumented.xml

@@ -1449,6 +1449,8 @@
 <Br/>
 <C>SwanBianchiCriterion</C>&nbsp;&nbsp;&nbsp;&nbsp;<B>Examples:</B> <Br/>
 <Br/>
+<C>SwanBianchiCriterion_alt</C>&nbsp;&nbsp;&nbsp;&nbsp;<B>Examples:</B> <Br/>
+<Br/>
 <C>SylowSubgroupOfCatOneGroup</C>&nbsp;&nbsp;&nbsp;&nbsp;<B>Examples:</B> <Br/>
 <Br/>
 <C>SymmetricCentre</C>&nbsp;&nbsp;&nbsp;&nbsp;<B>Examples:</B> <Br/>

lib/Congruence/bianchi.gi

@@ -112,7 +112,7 @@ fi;
 
 #fi;
 od;
-
+Add(U,[1,0,1]);      #Added July 2025
 return SSortedList(U);                       #####
 end);                                        #####
 ##################################################
@@ -1061,9 +1061,9 @@ end);                                           #####
 ###################################################
 ###################################################
 InstallGlobalFunction(UnimodularPairsReduced_NN, #####
-function(OQ,LL)                               #####
+function(OQ,LL)                                  #####
 local L, Lines, Points, K, K3, E,EE, V, VV,
-fn, fn2, v, w, h, dist, bool, C,D,DD,i,F,S,M;
+fn, fn2, v, w, h, dist, bool, BOOL, C,D,DD,i,F,S,M;
 
 #L:=QQNeighbourhoodOfUnimodularPairs(OQ,LL);
 if LL=[] then return [LL,[]]; fi;
@@ -1079,6 +1079,7 @@ DD:=Filtered([1..K!.nrSimplices(2)], v-> IsQQUnimodularPair(OQ,L[K3[v][1]])
 or IsQQUnimodularPair(OQ,L[K3[v][2]])
 or IsQQUnimodularPair(OQ,L[K3[v][3]]) );
 #Need to check that this is OK here
+
 S:=K3{DD};
 Points:=Points{DD};
 
@@ -1123,18 +1124,20 @@ od;
 
 L:=L{DD};
 L:=QQNeighbourhoodOfUnimodularPairs(OQ,L); 
+L:=SSortedList(L);
+
 
 VV:=Filtered(VV,v->v[1] in DD and v[2] in DD and v[3] in DD);
 M:=List(VV,v->Position(K!.simplicesLst[3],[v[1],v[2],v[3]]));
 M:=Difference([1..Length(K!.Points)], M);
 for i in M do
 K!.Points[i]:=fail;
-K!.Heights:=-infinity;
+#K!.Heights:=-infinity;
 od;
 
 
 return [L,K];                                    #####
-end);                                        #####
+end);                                            #####
 ##################################################
 ##################################################
 
@@ -1172,20 +1175,27 @@ ABI:=AbsInt(BI);
 ###############################
 
 HAPRECORD:=[
-[ 1, 1 ],[ 2, 1 ],[ 3, 1 ],[ 5, 20 ],[ 6, 24 ],[ 7, 1 ],[ 10, 40 ],[ 11, 1 ],[ 13, 52 ],[ 14, 56 ],[ 15, 15 ],[ 17, 68 ],[ 19, 4 ],[ 21, 84 ],[ 22, 88 ],[ 23, 18 ],[ 26, 104 ],[ 29, 169 ],[ 30, 121 ],[ 31, 16 ],[ 33, 132 ],[ 34, 9 ],[ 35, 35 ],[ 37, 25 ],[ 38, 4 ],[ 39, 39 ],[ 41, 25 ],[ 42, 25 ],[ 43, 9 ],[ 46, 25 ],[ 47, 24 ],[ 51, 51 ],[ 53, 25 ],[ 55, 56 ],[ 57, 49 ],[ 59, 27 ],[ 67, 16 ],[ 71, 48 ],[ 79, 40 ],[ 83, 33 ],[ 87, 87 ],[ 91, 91 ],[ 95, 95 ],[ 103, 56 ],[ 107, 36 ],[ 111, 111 ],[ 115, 115 ],[ 119, 25 ],[ 123, 123 ],[ 127, 64 ],[ 131, 45 ],[ 139, 55 ],[ 143, 9 ],[ 151, 80 ],[ 155, 155 ],[ 163, 53 ],[167,384],
-[ 179, 155]
+[ 1, 1 ],[ 2, 1 ],[ 3, 1 ],[ 5, 20 ],[ 6, 24 ],[ 7, 1 ],[ 10, 40 ],[ 11, 1 ],[ 13, 52 ],[ 14, 56 ],[ 15, 15 ],[ 17, 68 ],[ 19, 5 ],[ 21, 84 ],[ 22, 88 ],[ 23, 18 ],[ 26, 121 ],[ 29, 169 ],[ 30, 169 ],[ 31, 20 ],[ 33, 528 ],[ 34, 225 ],[ 35, 35 ],[ 37, 289 ],[ 38, 4 ],[ 39, 39 ],[ 41, 361 ],[ 42, 672 ],[ 43, 9 ],
+#[ 46, 25 ],
+[ 47, 36 ],[ 51, 51 ],
+#[ 53, 25 ],
+[ 55, 56 ],
+#[ 57, 49 ],
+[ 59, 36 ],[ 67, 23 ],[ 71, 64 ],[ 79, 64 ],[ 83, 36 ],[ 87, 87 ],[ 91, 91 ],[ 95, 95 ],[ 103, 64 ],[ 107, 64 ],[ 111, 111 ],[ 115, 115 ],
+#[ 119, 25 ],
+[ 123, 123 ],[ 127, 121 ],[ 131, 100 ],[ 139, 100 ],[ 143, 576 ],[ 151, 110 ],[ 155, 155 ],[159,240],[ 163, 53 ],[167,384],[ 179, 144], [199,196]
 ];;
                  #HAPRECORD contains some precomuted [d,r] for which Swan's
                  #criterion is satisfied for the given norm r.
 #HAPRECORD:=[];  #Uncomment this line to calculate HAPRECORD entries from 
-                 #scratch. The value [179,155] was only partialy checked (up 
-                 #to norm r=5000).
+                 #scratch.  
 
 if Length(arg)=2 then pos:=arg[2];
 else
 
 pos:=Position(List(HAPRECORD,x->x[1]),ABI);
 if pos =fail or pos=0 then pos:=infinity;
+Print("Try \n  P:=BianchiPolyhedron(OQ,N);\nfor some guessed positive integer value of N and then try\n  SwanBianchiCriterion(P);\nto test if the value of N was large enough. If the test returns false then you'll need to try a larger value of N.\n\nA successful value of N can be stored as a pair [d,N] in the list HAPRECORD which can be edited manually in the file hap/lib/Congruence/bianchi.gi .\n\n");
 else pos:=HAPRECORD[pos][2]; fi;
 
 fi;
@@ -1198,7 +1208,7 @@ bool:=true;
 L:=[];
 
 while bool do
-N:=N+1;
+N:=N+1; 
 if Length(arg)>1 then
 #Print("Adding hemispheres of squared radius ",1/NRMS[N],"\n");
 fi;
@@ -1221,7 +1231,7 @@ L:=K[1]; K:=K[2];
 ###########CHECK SWAN'S CONDITION REALLY IS MET
 if pos=infinity then 
 A:=BianchiPolyhedron(OQ!.bianchiInteger,L);
-A:=SwanBianchiCriterion(A);
+A:=SwanBianchiCriterion_alt(A);
 if not Length(A)=0 then 
 return CoverOfUnimodularPairs(OQ,N+1,true);
 fi;
@@ -1248,14 +1258,45 @@ if not Homology(Y,0)=[0] then return false; fi;
 if not Homology(Y,1)=[] then return false; fi;
 return true; 
 end);
+##################################################
+###############################################
+
 ##################################################
 ##################################################
+InstallGlobalFunction(SwanBianchiCriterion,
+function(P)
+local mr, mv, R, L,LL, i, u, Points;
 
+mr:=P!.minRadius;
+mv:=P!.minVertexHeight;
+if IsInt(1/mv) then R:=1/mv;
+else R:= 1+Int(1/mv);
+fi;
+
+L:=UnimodularPairs(P!.ring,R);;
+LL:=UnimodularPairs(P!.ring,mr);;
+L:=Difference(L,LL);;
+L:=Filtered(L,x->IsQQUnimodularPair(P!.ring,x));;
+L:=Filtered(L,x->not HAP_IsRedundantUnimodularPair(P!.ring,P!.unimodularPairs,x));
+
+Points:=Filtered([1..Length(P!.points)],i->P!.visibleHeights[i]>0);
+
+for u in L do
+for i in Points do
+if P!.visibleHeights[i] < HAP_HeightOfPointOnSphere(P!.ring,P!.points[i],u) then return false; fi;
+od;
+od;
 
+return true;
 
+end);
 ##################################################
 ##################################################
-InstallGlobalFunction(SwanBianchiCriterion,
+
+
+##################################################
+##################################################
+InstallGlobalFunction(SwanBianchiCriterion_alt,
 function(arg)
 local  PP,P,F,A,K,C,CC,D,H, nrmL, L, S, S1, v,b,x,i,h,s1,s2,t1,t2;
 
@@ -1340,7 +1381,7 @@ end);
 #####################################################
 InstallGlobalFunction(BianchiPolyhedron,
 function(arg)
-local d,K, P,C, OQ, F, H, L,M,i,x,N;
+local d,K, P,C, OQ, F, H, L,M,i,x,N,s;
 
 d:=arg[1];
 if d>=0 then
@@ -1402,8 +1443,20 @@ P!.cusps:=C;
 
 
 
-
+L:=K[2]!.unimodularPairs;
 H:=P!.heights;
+############
+for i in [1..Length(H)] do
+if H[i]>0 then
+for s in L do 
+if HAP_HeightOfPointOnSphere(OQ,K[2]!.Points[i],s)!.rational>H[i] then
+H[i]:=-infinity;
+fi;
+od;
+fi;
+od;
+############
+P!.visibleHeights:=1*H;
 H:=Filtered(H,x->x>0);
 if Length(H)>0 then
 H:=Minimum(H);

lib/Congruence/cong.gi

@@ -5,9 +5,8 @@ InstallMethod(RightTransversal,
 "right transversal for finite index subgroups of SL(2,Integers)",
 [IsMatrixGroup,IsMatrixGroup],
 function(H,HH);
-if not ( IsHapSL2ZSubgroup(H)) then TryNextMethod(); fi;
-#Print("HAP_RightTransversalSL2ZSubgroups\n");
-if IndexInSL2Z(H)=1 then
+if not ( IsHapSL2ZSubgroup(H) or IsHapSL2ZSubgroup(HH)) then TryNextMethod(); fi;
+if H=SL(2,Integers) then
 return HAP_RightTransversalSL2ZSubgroups(H,HH);
 else
 return HAP_RightTransversalSL2ZSubgroups_alt(H,HH);

lib/Congruence/quadraticIntegers.gd

@@ -113,6 +113,7 @@ DeclareGlobalFunction("UnimodularIntersectingLine");
 DeclareGlobalFunction("NeighbourhoodOfUnimodularPairs");
 DeclareGlobalFunction("HAP_VertexHeights");
 DeclareGlobalFunction("SwanBianchiCriterion");
+DeclareGlobalFunction("SwanBianchiCriterion_alt");
 DeclareGlobalFunction("QQNeighbourhoodOfUnimodularPairs");
 DeclareGlobalFunction("QNeighbourhoodOfUnimodularPairs");
 DeclareGlobalFunction("IsQUnimodularPair");

version

@@ -1 +1 @@
-1.68
+1.69

www/SideLinks/About/aboutGraphsOfGroups.html

@@ -184,7 +184,7 @@
 hyperbolic space. </small></big><big><small>A <span
  style="font-style: italic;">Fuchsian group</span> is a discrete
 subgroup of PSL(2,<span style="font-family: helvetica,arial,sans-serif;">R</span>)
-and as such acts on the hyperbolic plane. A "fundamental domain" for a co-finite 
+and as such acts on the hyperbolic plane. A "fundamental domain" for a co-finite volume  
 Kleinian or Fuchsian group G gives rise to a tessellation of hyperbolic
 3- or 2-space. Let X denote the 1-skeleton of this tessellation. Then G
 acts on (possibly a subdivision of) X in such a way that no edge is inverted. The quotient graph
@@ -206,7 +206,7 @@
           <tr>
             <td
  style="vertical-align: top; background-color: rgb(204, 255, 255);">Let
-G be a co-finite Fuchsian group. Let Y be the graph of groups arising
+G be a co-finite area Fuchsian group. Let Y be the graph of groups arising
 from G and a fundamental domain. Let P be the fundamental group of Y.
 Then the "obvious" quotient homomorphism P&#8594;G induces an isomorphism<br>
             <div style="text-align: center;"><br>

www/download/downloadContent.html

@@ -19,23 +19,23 @@ <h3>Download Instructions</h3>
 </p>
 <ul>
   <li>First download the file <a
- href="https://github.com/gap-packages/hap/releases/download/v1.68/hap-1.68.tar.gz">hap1.68.tar.gz</a>
+ href="https://github.com/gap-packages/hap/releases/download/v1.69/hap-1.69.tar.gz">hap1.69.tar.gz</a>
 which contains the most recent development version of HAP to the
 subdirectory
 "pkg/" of GAP. If you don't have access to this subdirectory,
 then create a directory "pkg" in your home directory and download the
 file there. (If you'd prefer to download the most
 recent development version of HAP then download the file&nbsp; <a
- href="https://github.com/gap-packages/hap/releases/download/v1.47/hap-1.47.tar.gz">hap1.68-dev.tar.gz</a>
+ href="https://github.com/gap-packages/hap/releases/download/v1.47/hap-1.47.tar.gz">hap1.69-dev.tar.gz</a>
 instead.)<br>
   </li>
 </ul>
 <ul>
   <li>Change to directory "pkg/" and type "gunzip
-hap1.68.tar.gz"
+hap1.69.tar.gz"
 followed
 by "tar
--xvf hap1.68.tar" .</li>
+-xvf hap1.69.tar" .</li>
 </ul>
 <ul>
   <li>Start GAP. (If you have created "pkg" in your home
@@ -51,7 +51,7 @@ <h3>Download Instructions</h3>
   <li>Help on HAP can be found on the <a
  href="https://gap-packages.github.io/hap/" target="index">HAP
 home page</a> (a version of which is included in directory
-"pkg/Hap1.68/www" of the distribution).</li>
+"pkg/Hap1.69/www" of the distribution).</li>
 </ul>
 <ul>
   <li>A few of HAP's (optional) functions rely on Polymake
@@ -67,7 +67,7 @@ <h3>Download Instructions</h3>
   <li>Performance can be improved by using a compiled
 version of the HAP library. The following steps will produce a compiled
 version. <br>
-(1) Change to the directory "pkg/Hap1.68/" .<br>
+(1) Change to the directory "pkg/Hap1.69/" .<br>
 (2) Edit the file "compile" so that: PKGDIR is equal to the path to the<br>
 directory "pkg" where your GAP packages are stored; GACDIR is equal to
 the<br>
@@ -78,7 +78,7 @@ <h3>Download Instructions</h3>
 <ul>
   <li>Should you want to return to an uncompiled version, change
 to the directory<br>
-"pkg/Hap1.68/" and type "./uncompile".</li>
+"pkg/Hap1.69/" and type "./uncompile".</li>
 </ul>
 </div>
 </body>