A Combinatorial Principle]A Combinatorial Principle Equivalent to the Existence
نویسنده
چکیده
As a consequence of identifying the principle described in the title, we prove that for any uncountable cardinal λ, if there is a λ-free Whitehead group of cardinality λ which is not free, then there are many “nice” Whitehead groups of cardinality λ which are not free.
منابع مشابه
Some Algebraic and Combinatorial Properties of the Complete $T$-Partite Graphs
In this paper, we characterize the shellable complete $t$-partite graphs. We also show for these types of graphs the concepts vertex decomposable, shellable and sequentially Cohen-Macaulay are equivalent. Furthermore, we give a combinatorial condition for the Cohen-Macaulay complete $t$-partite graphs.
متن کاملA class of strong diamond principles
In the context of large cardinals, the classical diamond principle 3κ is easily strengthened in natural ways. When κ is a measurable cardinal, for example, one might ask that a 3κ sequence anticipate every subset of κ not merely on a stationary set, but on a set of normal measure one. This is equivalent to the existence of a function ` ... κ → Vκ such that for any A ∈ H(κ) there is an embedding...
متن کاملA Very Weak Square Principle
In this paper we explicate a very weak version of the principle discovered by Jensen who proved it holds in the constructible universe L. This principle is strong enough to include many of the known applications of , but weak enough that it is consistent with the existence of very large cardinals. In this section we show that this principle is equivalent to a common combinatorial device, which ...
متن کاملA Maximum Principle for Combinatorial Yamabe Flow
In his proof of Andreev’s theorem, Thurston in [1] introduced a conformal geometric structure on two dimensional simplicial complexes which is an analogue of a Riemannian metric. He then used a version of curvature to prove the existence of circle-packings (see also Marden-Rodin [2] for more exposition). Techniques very similar to elliptic partial differential equation techniques were used by Y...
متن کاملA Variational Principle for Weighted Delaunay Triangulations and Hyperideal Polyhedra
We use a variational principle to prove an existence and uniqueness theorem for planar weighted Delaunay triangulations (with non-intersecting site-circles) with prescribed combinatorial type and circle intersection angles. Such weighted Delaunay triangulations may be interpreted as images of hyperbolic polyhedra with one vertex on and the remaining vertices beyond the infinite boundary of hype...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2008