From 51d898ca7ded76ed76dead486648dd121b40fdf9 Mon Sep 17 00:00:00 2001
From: Max Horn <max@quendi.de>
Date: Wed, 30 May 2018 16:06:57 +0200
Subject: [PATCH] Take advantage of implications to simplify some code

---
 lib/coll.gi     |  2 +-
 lib/grp.gi      |  7 +++----
 lib/grpmat.gi   |  4 +---
 lib/grppc.gi    |  5 +----
 lib/modulrow.gi |  4 ++--
 lib/vspcrow.gi  | 12 +++++-------
 6 files changed, 13 insertions(+), 21 deletions(-)

diff --git a/lib/coll.gi b/lib/coll.gi
index f788cf5b26..f55867e621 100644
--- a/lib/coll.gi
+++ b/lib/coll.gi
@@ -3079,7 +3079,7 @@ local filt;
     fi;
     return;
   fi;
-  if sz=0 then filt:=IsEmpty and IsNonTrivial; # IsNonTrivial hold
+  if sz=0 then filt:=IsEmpty;
   elif sz=1 then filt:=IsTrivial;
   elif sz=infinity then filt:=IsNonTrivial and HasIsFinite;
   else filt:=IsNonTrivial and IsFinite;
diff --git a/lib/grp.gi b/lib/grp.gi
index 96f5b9bd18..86999c97ce 100644
--- a/lib/grp.gi
+++ b/lib/grp.gi
@@ -4316,12 +4316,12 @@ function(fam,filt,gens,id,isgroup)
       fi;
       if id<>fail then # cannot do identity in magma
         if ForAny(gens,x->x<>id) then
-          filt:=filt and HasIsTrivial and IsNonTrivial;
+          filt:=filt and IsNonTrivial;
           if isgroup and Length(gens)<=1 then # cyclic not for magmas
             filt:=filt and IsCyclic;
           fi;
         else
-          filt:=filt and IsTrivial and HasIsNonTrivial;
+          filt:=filt and IsTrivial;
         fi;
       fi;
     elif isgroup and Length(gens)<=1 then # cyclic not for magmas
@@ -4379,8 +4379,7 @@ local G,fam,typ;
   fam:= CollectionsFamily( FamilyObj( id ) );
 
   typ:=IsGroup and IsAttributeStoringRep
-        and HasGeneratorsOfMagmaWithInverses and HasOne and IsTrivial and
-        HasIsEmpty and HasIsNonTrivial;
+        and HasGeneratorsOfMagmaWithInverses and HasOne and IsTrivial;
   typ:=NewType(fam,typ);
 
   G:= rec();
diff --git a/lib/grpmat.gi b/lib/grpmat.gi
index 9caaeecb7d..00d0778691 100644
--- a/lib/grpmat.gi
+++ b/lib/grpmat.gi
@@ -868,9 +868,7 @@ local G,fam,typ,f;
 
   if not IsFinite(gens) then TryNextMethod(); fi;
   typ:=MakeGroupyType(FamilyObj([id]), IsGroup and IsAttributeStoringRep 
-            and HasGeneratorsOfMagmaWithInverses and IsFinitelyGeneratedGroup
-            and HasIsEmpty and IsFinite and HasOne
-            and IsTrivial and HasIsNonTrivial,
+            and HasGeneratorsOfMagmaWithInverses and HasOne and IsTrivial,
             gens,id,true);
 
   f:=DefaultScalarDomainOfMatrixList([id]);
diff --git a/lib/grppc.gi b/lib/grppc.gi
index ad1a10f292..e4018118f0 100644
--- a/lib/grppc.gi
+++ b/lib/grppc.gi
@@ -412,10 +412,7 @@ local G,fam,typ,pcgs;
 
   # pc groups are always finite and gens is finite.
   typ:=IsGroup and IsAttributeStoringRep 
-        and HasGeneratorsOfMagmaWithInverses and HasOne
-        and IsFinite and IsFinitelyGeneratedGroup
-        and IsTrivial and HasIsNonTrivial
-        and HasIsEmpty and IsSolvableGroup
+        and HasGeneratorsOfMagmaWithInverses and HasOne and IsTrivial
         and HasFamilyPcgs and HasHomePcgs and HasGeneralizedPcgs;
   typ:=NewType(fam,typ);
 
diff --git a/lib/modulrow.gi b/lib/modulrow.gi
index efc9d07a15..546be4f133 100644
--- a/lib/modulrow.gi
+++ b/lib/modulrow.gi
@@ -35,9 +35,9 @@ local M,typ;   # the free module record, result
     fi;
 
     if n=0 then
-      typ:=typ and IsTrivial and HasIsNonTrivial and IsFinite;
+      typ:=typ and IsTrivial;
     else
-      typ:=typ and HasIsTrivial and IsNonTrivial;
+      typ:=typ and IsNonTrivial;
     fi;
 
     if n<>infinity and HasIsFinite(R) and IsFinite(R) then
diff --git a/lib/vspcrow.gi b/lib/vspcrow.gi
index 80f5f9b78a..df699b2ad7 100644
--- a/lib/vspcrow.gi
+++ b/lib/vspcrow.gi
@@ -64,9 +64,9 @@ InstallMethod( LeftModuleByGenerators,
     fi;
 
     if Length(mat)>0 and ForAny(mat,x->not IsZero(x)) then
-      typ:=typ and HasIsTrivial and IsNonTrivial;
+      typ:=typ and IsNonTrivial;
     else
-      typ:=typ and IsTrivial and HasIsNonTrivial;
+      typ:=typ and IsTrivial;
     fi;
 
     if HasIsFinite(F) then
@@ -98,9 +98,7 @@ InstallMethod( LeftModuleByGenerators,
     fi;
 #T explicit 2nd argument above!
 
-    typ:=IsAttributeStoringRep and HasIsEmpty and IsFiniteDimensional
-         and IsGaussianRowSpace and IsTrivial and HasIsNonTrivial and
-         IsFinite;
+    typ:=IsAttributeStoringRep and IsGaussianRowSpace and IsTrivial;
 
     V:= Objectify( NewType( CollectionsFamily( FamilyObj( F ) ),typ),
                    rec() );
@@ -132,9 +130,9 @@ InstallMethod( LeftModuleByGenerators,
     fi;
 
     if Length(mat)>0 and ForAny(mat,x->not IsZero(x)) then
-      typ:=typ and HasIsTrivial and IsNonTrivial;
+      typ:=typ and IsNonTrivial;
     else
-      typ:=typ and IsTrivial and HasIsNonTrivial;
+      typ:=typ and IsTrivial;
     fi;
 
     if HasIsFinite(F) then