Contents 1. Introduction 2 2. Preliminaries 4 2.1. Some results on ...

(127)=(Cδ C Q ̂QQ) (◦ ∆ C Q ̂QQ)◦ (CQlQ) ◦ (CQP xQ) ◦ (CQP Qδ D )143∆ C=Qis a com=Qis a bicom=◦ (CQδ D D) ◦ ( Cρ D QD ) ◦ (C ρ Q D ) ◦ ρ D Q(Cδ C Q ̂QQ)◦ (CCQlQ) ◦ (CCQP xQ) ◦ (CCQP Qδ D ) ◦ (CCQδ D D)◦ ( CCρ D QD ) ◦ ( ∆ C QD ) ◦ (C ρ Q D ) ◦ ρ D Q(Cδ C Q ̂QQ)◦ (CCQlQ) ◦ (CCQP xQ) ◦ (CCQP Qδ D ) ◦ (CCQδ D D)◦ ( CCρ D QD ) ◦ ( C C ρ Q D ) ◦ (C ρ Q D ) ◦ ρ D Q(Cδ C Q ̂QQ)◦ (CCQlQ) ◦ (CCQP xQ) ◦ (CCQP Qδ D ) ◦ (CCQδ D D)◦ ( C C ρ Q DD ) ◦ ( Cρ D QD ) ◦ (C ρ Q D ) ◦ ρ D QC ρ Q=(Cδ C Q ̂QQ))◦(C C ρ Q ̂QQ ◦ (CQlQ) ◦ (CQP xQ) ◦ (CQP Qδ D ) ◦ (CQδ D D)Qis a bicom=◦ ( Cρ D QD ) ◦ (C ρ Q D ) ◦ ρ D Q(Cδ C Q ̂QQ))◦(C C ρ Q ̂QQ ◦ (CQlQ) ◦ (CQP xQ) ◦ (CQP Qδ D )◦ (CQδ D D) ◦ (C ρ Q DD ) ◦ ( ρ D QD ) ◦ ρ D QC ρ Q=(Cδ C Q ̂QQ))◦(C C ρ Q ̂QQ (C )◦ ρ Q ̂QQ ◦ (QlQ) ◦ (QP xQ) ◦ (QP Qδ D )(127)=(127)=Qis a bicom=δ C=◦ (Qδ D D) ◦ ( ρ D QD ) ◦ ρ D Q) ((CQδ D ̂QQ ◦ Cρ D ̂QQ) (C )Q ◦ ρ Q ̂QQ ◦ (QlQ) ◦ (QP xQ) ◦ (QP Qδ D )◦ (Qδ D D) ◦ ( ρ D QD ) ◦ ρ D Q) ((CQδ D ̂QQ ◦ Cρ D ̂QQ) (C )Q ◦ ρ Q ̂QQ ◦ (QlQ) ◦ (QP xQ) ◦ (QP Qδ D )◦ (δ C QD) ◦ (C ρ Q D ) ◦ ρ D Q) ((CQδ D ̂QQ ◦C ρ Q D ̂QQ) (◦ ρ D ̂QQ)Q ◦ (QlQ) ◦ (QP xQ) ◦ (QP Qδ D )◦ (δ C QD) ◦ (C ρ Q D ) ◦ ρ D Q) ((CQδ D ̂QQ ◦C ρ Q D ̂QQ) (◦ ρ D ̂QQ)Q ◦ (QlQ) ◦ (QP xQ) ◦ (δ C QP Q)Hence we obtain◦ (CQδ D ) ◦ (C ρ Q D ) ◦ ρ D Q(Q ̂Qτ)◦ τ(= QlQ ̂QQ) (◦ QP xQ ̂QQ) (◦ δ C QP Q ̂QQ) (◦C ρ Q P Q ̂QQ) (◦ δ C Q ̂QQ)=(QlQ ̂QQ) (◦ QP xQ ̂QQ)◦◦ (Cτ) ◦ C ρ Q(δ C QP Q ̂QQ))◦(CQδ D ̂QQ ◦(C ρ Q D ̂QQ)