Spline bases in classical function spaces on compact manifolds, Part II
Spline bases in classical function spaces on compact manifolds, Part I
Spline characterizations of H¹
Spline Representations of Functions in Besov-Triebel-Lizorkin Spaces on Rn.
Splines and pseudo-inverses
Split faces and ideal structure of operator algebras.
Split Faces and Projective Sets in a Metrizable Compact Convex Set.
Splitting maps and norm bounds for the cyclic cohomology of biflat Banach algebras
We revisit the old result that biflat Banach algebras have the same cyclic cohomology as C, and obtain a quantitative variant (which is needed in separate, joint work of the author on the simplicial and cyclic cohomology of band semigroup algebras). Our approach does not rely on the Connes-Tsygan exact sequence, but is motivated strongly by its construction as found in [2] and [5].
Spontaneously broken symmetries
Spreading basic sequences and subspaces of James' quasi-reflexive space.
Spreading sequences in JT
We prove that a normalized non-weakly null basic sequence in the James tree space JT admits a subsequence which is equivalent to the summing basis for the James space J. Consequently, every normalized basic sequence admits a spreading subsequence which is either equivalent to the unit vector basis of or to the summing basis for J.
Square functions associated to Schrödinger operators
We characterize geometric properties of Banach spaces in terms of boundedness of square functions associated to general Schrödinger operators of the form ℒ = -Δ + V, where the nonnegative potential V satisfies a reverse Hölder inequality. The main idea is to sharpen the well known localization method introduced by Z. Shen. Our results can be regarded as alternative proofs of the boundedness in H¹, and BMO of classical ℒ-square functions.
Square functions, bounded analytic semigroups, and applications
To any bounded analytic semigroup on Hilbert space or on -space, one may associate natural ’square functions’. In this survey paper, we review old and recent results on these square functions, as well as some extensions to various classes of Banach spaces, including noncommutative -spaces, Banach lattices, and their subspaces. We give some applications to functional calculus, similarity problems, multiplier theory, and control theory.
Square roots and quasi-square roots in locally multiplicatively convex algebras
Square roots of elements with an unbounded spectrum
Square roots of perturbed subelliptic operators on Lie groups
We solve the Kato square root problem for bounded measurable perturbations of subelliptic operators on connected Lie groups. The subelliptic operators are divergence form operators with complex bounded coefficients, which may have lower order terms. In this general setting we deduce inhomogeneous estimates. In case the group is nilpotent and the subelliptic operator is pure second order, we prove stronger homogeneous estimates. Furthermore, we prove Lipschitz stability of the estimates under small...
S-rationally convex domains and the approximation of Silva-holomorphic functions by S-rational functions
Stabile Maße auf Badrikianschen Räumen.
Stabilität starkstetiger, positiver Operatorhalbgruppen auf C*-Algebren.
Stabilité des -algèbres de feuilletages
Soit la -algèbre, ou bien réduite ou bien maximale, associée à la variété feuilletée , et la -algèbre élémentaire des opérateurs compacts. Alors, si dim, on montre que est isomorphe à .