partial proof of graham higman's conjecture related to coset diagrams

graham higman has defined coset diagrams for psl(2,ℤ). these diagrams are composed of fragments, and the fragments are further composed of two or more circuits. q. mushtaq has proved in 1983 that existence of a certain fragment γ of a coset diagram in a coset diagram is a polynomial f in ℤ[z]. higman has conjectured that, the polynomials related to the fragments are monic and for a fixed degree, there are finite number of such polynomials. in this paper, we consider a family ϝ of fragments such that each fragment in ϝ contains one vertex fixed byf_v [(〖xy〗^(-1) )^(s_1 ) (xy)^(s_2 ) (〖xy〗^(-1) )^(s_3 ),(xy)^(q_1 ) (〖xy〗^(-1) )^(q_2 ) (xy)^(q_3 ) ]where s₁,s₂,s₃,q₁,q₂,q₃∈ℤ⁺, and prove higman's conjecture for the polynomials obtained from the fragments in ϝ.