#We find all primitive subgroups of $GL(8,7)$ with parameters $e=4$, $a=2$. In this case $b=2$ divides $a=2$. #In the notations of Theorem 5.1, if $H$ is a primitive solvable subgroup, then it possesses a series #$$1 e:=4;; p:=11;; d:=8;; a:=2;; b:=2;; #Now we generate the list of all primitive subgroups in $GL(e,p)=GL(4,11)$, using standart function of the package IRREDSOL gap> l0:=AllIrreducibleSolvableMatrixGroups(Degree, d/2, Field, GF(p), IsPrimitiveMatrixGroup, true);; #In this list we choose subgroups, whose order is divisible by the order of $F$ in the notations of Theorem 5.1 gap> l1:=Filtered(l0,x-> (Order(x) mod ((p-1)*e*e)) = 0);; #In view of Lemma 5.4, we choose subgroups satisfying $\vert A/F\vert\in \{20,72\}$ and collect these subgroups in the list l2. gap> l2:=Filtered(l1,x-> (Order(x)/((p-1)*e*e)) in [20,72]);; Size(l2); 2 #Now we need to make an embedding of the primitive solvable subgroups of $GL(e,p)=GL(4,11)$ into $GL(d,p)=GL(8,11)$. #First each $G\leq GL(4,11)$ we embed in $GL(8,11)$ by taking $I_2\otimes G$ #First we produce generators of subgroups from the list l2 gap> gens:=[];; gap> for k in l2 do > Append(gens,[GeneratorsOfGroup(k)]);; > od; #Each matrix $g$ in gens we substitute by $I_2\otimes g$. gap> genS:=[];; gap> for i in [1..Size(gens)] do > genS[i]:=[]; > for j in gens[i] do > Append(genS[i],[KroneckerProduct(IdentityMat(2,Z(11)),j)]); > od; > od; #Now we add $t\otimes I_e$, $s\otimes I_e$ to the list of generators, where t is a Singer cycle of $GL(d/e,p)$, and $t^s=t^p$. gap> bas:= Basis(AsVectorSpace( GF(p),GF(p^2) ) );; gap> t:=BlownUpMat(bas,[[Z(p^a)]]);; gap> s:=RepresentativeAction(GL(a,p),t,t^p);; gap> Ie:=IdentityMat(e,GF(p));; td:=KroneckerProduct(t,Ie);; sd:=KroneckerProduct(s,Ie);; #Now we add generators td and sd to the generators of subgroups in the list gap> for k in genS do gap> Append(k,[td,sd]);; gap> od; #Now we run the following loop. Each entry of the list result has three items: the first is the #number of the group in the list genS, the second is the order of the group, and the third is the order of the stabilizer of v in H. #If the order of the stabilizer is 1, then |v^H=|H| and Corollary 2.5 can be applied. gap> z:=Z(p);; v:=[z,z^3,z^7,z^9,0*z,z^2,z^4,z^5];; gap> result:=[];; i:=0;; gap> for k in genS do > H:=Subgroup(GL(8,11),k);; i:=i+1;; > n:=Size(H);; m:=Size(v^H);; > result[i]:=[i,n,n/m]; > Display(result[i]); > od; [ 1, 276480, 1 ] [ 2, 76800, 1 ]