𝔖 Bobbio Scriptorium
✦   LIBER   ✦

On Disjoint Chains of Subsets

✍ Scribed by Eric Lehman; Dana Ron


Publisher
Elsevier Science
Year
2001
Tongue
English
Weight
166 KB
Volume
94
Category
Article
ISSN
0097-3165

No coin nor oath required. For personal study only.

✦ Synopsis


We prove the following theorem concerning the poset of all subsets of [n] ordered by inclusion. Consider any two equal-size families of subsets of [n], S and R, where within each family all subsets have the same number of elements. Suppose there exists a bijection ,: S [ R such that A#f (A) for all A # S. Then there exist |S| disjoint saturated chains containing all the subsets in S and R.

2001


πŸ“œ SIMILAR VOLUMES


Disjoint subsets of integers having a co
✍ Kiyoshi Ando; Severino Gervacio; Mikio Kano πŸ“‚ Article πŸ“… 1990 πŸ› Elsevier Science 🌐 English βš– 262 KB

We prove that for positive integers n, m and k, the set (1, 2, . , n} of integers contains k disjoint subsets having a constant sum m if and only if 2k -1 G m c n(n + 1)/(2k).

Open maps on manifolds which do not admi
✍ Hisao Kato; Michael Levin πŸ“‚ Article πŸ“… 2000 πŸ› Elsevier Science 🌐 English βš– 95 KB

Let X and Y be compacta. A map f : X β†’ Y is said to satisfy Bula's property if there exist disjoint closed subsets F 0 and Dranishnikov constructed an open surjective map of infinite-dimensional compacta with fibers homeomorphic to a Cantor set which does not satisfy Bula's property. We construct a