It has been proved that algebraic polynomials P are dense in the space Lp(R, dμ), p∈ (0,∞), iff the measure μ is representable as dμ = wp dν with a finite non-negative Borel measure ν and an upper semi-continuous function w : R → R+ : = [0,∞) such that P is a dense subset of the space C0 w : = {f ∈ C(R) : w(x)f(x) → 0 as |x| → ∞} equipped with the seminorm ‖f‖w := supx∈R w(x)|f(x)|. The similar...

An important open problem in operator theory is the invariant subspace problem. Since the problem is solved for all finite dimensional complex vector spaces of dimension at least 2, H denotes a separable Hilbert space whose dimension is infinite. It is enough to think for a contraction T , that is, ‖T‖ ≤ 1 on H . Thus, T ( 6= 0) denotes a contraction in L(H). Let λ always denote an element of t...

We show that an infinite-dimensional complete linear space X has: • a dense hereditarily Baire Hamel basis if |X| ≤ c; • a dense non-meager Hamel basis if |X| = κ = 2 for some cardinal κ. According to Corollary 3.4 of [BDHMP] each infinite-dimensional separable Banach space X has a non-meager Hamel basis. This is a special case of Theorem3.3 of [BDHMP], asserting that an infinite-dimensional Ba...

We prove that for any n ≥ 1 there exist n × n matrices A and B such that for any vector x ∈ R with a nonzero first component, the orbit of x under the action of the semigroup generated by A and B is dense in R. As a corollary, we prove that for a large set of diagonal matrices A and B and any vector V with nonzero entries, the orbit of any vector under the semigroup generated by the affine maps...

A subset Y of a space X is Gδ-dense if it intersects every nonempty Gδ-set. The Gδ-closure of Y in X is the largest subspace of X in which Y is Gδ-dense. The space X has a regular Gδ-diagonal if the diagonal of X is the intersection of countably many regular-closed subsets of X ×X. Consider now these results: (a) [N. Noble, 1972] every Gδ-dense subspace in a product of separable metric spaces i...

Let X be a smooth affine curve over a field k of characteristic p > 0 and E an overconvergent F a-isocrystal on X for some positive integer a. We prove that after replacing k by some finite purely inseparable extension, there exists a finite separable morphism X ′ → X, the pullback of E along which extends to a log-F a-isocrystal on a smooth compactification of X . This resolves a weak form of ...

Follow up what we will offer in this article about pythagorean hodograph curves algebra and geometry inseparable. You know really that this book is coming as the best seller book today. So, when you are really a good reader or you're fans of the author, it does will be funny if you don't have this book. It means that you have to get this book. For you who are starting to learn about something n...

For a hundred of years electricity and its delivery were thought to be inseparable. Since the late-1980s and early-1990s things began to change. Due to diverse reasons [13] both developed and developing countries began to abandon the idea of an electricity industry vertically integrated to adopt a new model that allows competition and choice in electricity. The idea of commercial separation of ...

When two patterns occur equally often in a set of permutations, we say that these patterns are equipopular. Using both structural and analytic tools, we classify the equipopular patterns in the set of separable permutations. In particular, we show that the number of equipopularity classes for length n patterns in the separable permutations is equal to the number of partitions of the integer n− 1.