منابع مشابه
Uniquely D-colourable Digraphs with Large Girth
Let C and D be digraphs. A mapping f : V (D) → V (C) is a Ccolouring if for every arc uv of D, either f(u)f(v) is an arc of C or f(u) = f(v), and the preimage of every vertex of C induces an acyclic subdigraph in D. We say that D is C-colourable if it admits a C-colouring and that D is uniquely Ccolourable if it is surjectively C-colourable and any two C-colourings of D differ by an automorphis...
متن کاملExtracting γ from Bs(d) → J/ψ KS and Bd(s) → D + − d(s) Dd(s)
A completely general parametrization of the time-dependent decay rates of the modes B s → J/ψ K S and B d → J/ψ K S is given, which are related to each other through the U-spin flavour symmetry of strong interactions. Owing to the interference of current–current and penguin processes, the B s → J/ψ K S observables probe the angle γ of the unitarity triangle. Using the U-spin symmetry, the overa...
متن کاملOn large (Δ, D, D, 1)-graphs
Concern about fault tolerance in the design of interconnection networks has aroused interest in finding large graphs such that the subgraphs obtained by deleting any set of up to s vertices have small diameter. Clearly, 1 ≤ s ≤ ∆ − 1, where ∆ is the maximum degree of the graph. Graphs of maximum degree ∆, diameter ≤ D and such that the graphs obtained by deletion of up to s vertices have diamet...
متن کاملLarge-D gravity and low-D strings.
We show that in the limit of a large number of dimensions a wide class of nonextremal neutral black holes has a universal near-horizon limit. The limiting geometry is the two-dimensional black hole of string theory with a two-dimensional target space. Its conformal symmetry explains the properties of massless scalars found recently in the large-D limit. For black branes with string charges, the...
متن کاملIght - D Imensional S Elf - D Ual S Paces ⋆
We discuss higher-dimensional gravitational instantons by studying appropriate self-duality equations for the spin connection. In seven and in eight dimensions, the corresponding spaces admit a covariantly constant spinor and, consequently, have holonomies in G 2 and Spin(7), respectively. We find a non-compact solution to the self-duality equations in eight dimensions in which the self-dual sp...
متن کاملذخیره 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: Discrete Applied Mathematics
سال: 1995
ISSN: 0166-218X
DOI: 10.1016/0166-218x(93)e0165-u