A sufficient condition that an operator be normal.

نویسندگان

چکیده

برای دانلود باید عضویت طلایی داشته باشید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

A Sufficient Condition That a C-Characteristic Be Geometric.

These inequalities express the fact that no curve of order k and defined at the p points can meet the net in more than yok points. Coble' has conjectured that the conditions (1) and (2) are sufficient as well as necessary. In this paper we will show that the conditions (2) are actually sufficient. Indeed, the less stringent set of inequalities given in (5) will suffice. The notation and point o...

متن کامل

A Sufficient Condition That a Mapping of Riemannian Manifolds Be a Fibre Bundle

2. Generalities [2; l]. If xGA, vi, v2(E.Xx, let (vu v2) denote the inner product that defines the Riemannian metric. If a: [0, l]—»A is a curve, let a':t-^a'(t) denote the tangent vector field to a. If v: H»(i)GI,(i) is a vector-field along a, let Av denote the covariant derivative of v along a [l]. Let us recall how it is defined by Elie Cartan's method of orthonormal moving frames: Suppose U...

متن کامل

A Simple Sufficient Condition That a Method of Summability Be Stronger than Convergence

and a method A of summability by means of which a given sequence Su S2, • • • is summable to <r as w—»oo. If a sequence sn is summable A, we say that A {sn} exists and that sn belongs to the summability field of A. If sn is summable A to <r, we say that A {sn} = <r. The method A is regular if A {sn} = lim sn whene...

متن کامل

A New Sufficient Condition for a Digraph to Be Hamiltonian

In 2] the following extension of Meyniels theorem was conjectured: If D is a digraph on n vertices with the property that d(x) + d(y) 2n ? 1 for every pair of non-adjacent vertices x; y with a common out-neighbour or a common in-neighbour, then D is Hamiltonian. We verify the conjecture in the special case where we also require that minfd + (x)+d ? (y); d ? (x)+d + (y)g n ?1 for all pairs of ve...

متن کامل

A sufficient condition for planar graphs to be 3-colorable

Planar graphs without 3-cycles at distance less than 4 and without 5-cycles are proved to be 3-colorable. We conjecture that, moreover, each plane graph with neither 5-cycles nor intersecting 3-cycles is 3-colorable. In this conjecture, none of the two assumptions can be dropped because there exist planar 4-chromatic graphs without 5-cycles, as well as planar 4chromatic graphs without intersect...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

ژورنال

عنوان ژورنال: Michigan Mathematical Journal

سال: 1974

ISSN: 0026-2285

DOI: 10.1307/mmj/1029001261