“…The possible values of pccd G are integers greater than or equal to −1 and ∞. It is known that if G = * n∈N G n and G n is a free abelian group of rank n, then pccd G = ∞, and if G is the Thompson group T , ⊕ ∞ i=1 Z, or GL n (K), where K is a subfield of the algebraic closure of Q, then pccd G = −1 [17,18].…”