On Dragilev type power Köthe spaces
Volume 120 / 1996
Studia Mathematica 120 (1996), 219-234 DOI: 10.4064/sm-120-3-219-234
A complete isomorphic classification is obtained for Köthe spaces $X = K(exp[χ(p - κ (i)) - 1/p]a_i)$ such that $X qd_≃ X^2$; here χ is the characteristic function of the interval [0,∞), the function κ: ℕ → ℕ repeats its values infinitely many times, and $a_i → ∞$. Any of these spaces has the quasi-equivalence property.