منابع مشابه
Knots in Collapsible and Non-Collapsible Balls
We construct the first explicit example of a simplicial 3-ball B15,66 that is not collapsible. It has only 15 vertices. We exhibit a second 3-ball B12,38 with 12 vertices that is collapsible and not shellable, but evasive. Finally, we present the first explicit triangulation of a 3-sphere S18,125 (with only 18 vertices) that is not locally constructible. All these examples are based on knotted ...
متن کاملVersatile collapsible rabbit cage.
The cage was designed for holding and breeding rabbits, and can also be used for holding cats for short periods. Single cages can be joined back to back: this larger cage can also be used for breeding rabbits, and the longer-term holding of cats. When not in use cages fold into compact units, saving storage space and labour, as many cages may be autoclaved, boiled or steamed at once. Repair, ma...
متن کاملCollapsible Polyhedra and Median Spaces
It is shown that a collapsible, compact, connected, simplicial polyhedron admits a cubical subdivision and a median convexity, such that all cubes are convex subspaces with a convexity of subcubes. Conversely, a compact, connected, cubical polyhedron with a convexity as described admits a collapsible simplicial subdivision. Such a convexity, when it exists, is uniquely determined by the corresp...
متن کاملCollapsible biclaw-free graphs
A graph is called biclaw-free if it has no biclaw as an induced subgraph. In this note, we prove that if G is a connected bipartite biclaw-free graph with δ(G) ≥ 5, then G is collapsible, and of course supereulerian. This bound is best possible.
متن کاملDoes a Rising Tide Lift All Boats?
Last year, an Institute of Medicine panel identified health care delivery and disparities as the nation’s top 2 priorities for comparative effectiveness research.1 We have long known that disparities in the delivery of cardiovascular care are pervasive and harmful; the literature is robust and clear. These disturbing disparities are most prominent for emerging hightechnology procedures. Compare...
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: Scientific American
سال: 1877
ISSN: 0036-8733
DOI: 10.1038/scientificamerican08111877-1327supp