Complemented Infinite Type Power Series Subspaces of Nuclear Fréchet Spaces.
The following result is proved: Let E be a complemented subspace with an r-finite-dimensional decomposition of a nuclear Köthe space λ(A). Then E has a basis.
New compound geometric invariants are constructed in order to characterize complemented embeddings of Cartesian products of power series spaces. Bessaga's conjecture is proved for the same class of spaces.
The following result is proved: Let denote a power series space of infinite or of finite type, and equip with its canonical fundamental system of norms, R ∈ 0,∞, 1 ≤ p < ∞. Then a tamely exact sequence (⁎) exists iff α is strongly stable, i.e. , and a linear-tamely exact sequence (*) exists iff α is uniformly stable, i.e. there is A such that for all K. This result extends a theorem of Vogt and Wagner which states that a topologically exact sequence (*) exists iff α is stable, i.e. .