Bh[g]-Sequences with Large Upper Density

Unconditional basic sequences in spaces of large density

We study the problem of the existence of unconditional basic sequences in Banach spaces of high density. We show, in particular, the relative consistency with GCH of the statement that every Banach space of density אω contains an unconditional basic sequence.

Weakly Null Sequences with Upper Estimates

Abstract. We prove that if (vi) is a normalized basic sequence and X is a Banach space such that every normalized weakly null sequence in X has a subsequence that is dominated by (vi), then there exists a uniform constant C ≥ 1 such that every normalized weakly null sequence in X has a subsequence that is C-dominated by (vi). This extends a result of Knaust and Odell, who proved this for the ca...

Weakly null sequences with upper `p-estimates

Weakly null sequences with upper lp-estimates

A Banach space X has property (S) if every weakly null sequence in BaX, the unit ball of X, has a subsequence which is C-dominated by the unit vector basis of c0 for some constant C < ∞. In [11] it was shown that if X has property (S), then the constant C can be chosen to be independent of the particular weakly null sequence in BaX. Here we generalize this result to the case of upper lp-estimates.

Upper Bound Analysis of Tube Extrusion Process Through Rotating Conical Dies with Large Mandrel Radius

In this paper, an upper bound approach is used to analyze the tube extrusion process through rotating conical dies with large mandrel radius. The material under deformation in the die and inside the container is divided to four deformation zones. A velocity field for each deformation zone is developed to evaluate the internal powers and the powers dissipated on all frictional and velocity disco...