Standard Examples as Subposets of Posets
نویسندگان
چکیده
منابع مشابه
Forcing Posets with Large Dimension to Contain Large Standard Examples
The dimension of a poset P , denoted dim(P ), is the least positive integer d for which P is the intersection of d linear extensions of P . The maximum dimension of a poset P with |P | ≤ 2n+ 1 is n, provided n ≥ 2, and this inequality is tight when P contains the standard example Sn. However, there are posets with large dimension that do not contain the standard example S2. Moreover, for each f...
متن کاملN-free posets as generalizations of series-parallel posets
N-free posets have recently taken some importance and motivated many studies. This class of posets introduced by Grillet [8] and Heuchenne [11] are very related to another important class of posets, namely the series-parallel posets, introduced by Lawler [12] and studied by Valdes et al. [21]. This paper shows how N-free posets can be considered as generalizations of series-parallel posets, by ...
متن کاملCobweb posets as noncommutative prefabs
A class of new type graded infinite posets with minimal element is introduced. These so called cobweb posets proposed recently by the present author constitute a wide range of new noncommutative and nonassociative prefab combinatorial schemes‘ examples with characteristic graded sub-posets as primes. These schemes are defined here via relaxing commutativity and associativity requirements impose...
متن کاملSet families with forbidden subposets
Let F be a family of subsets of {1, . . . , n}. We say that F is P -free if the inclusion order on F does not contain P as an induced subposet. The Turán function of P , denoted La∗(n, P ), is the maximum size of a P -free family of subsets of {1, . . . , n}. We show that La∗(n, P ) ≤ (4r + O( √ r)) ( n bn/2c ) if P is an r-element poset of height at most 2. We also show that La∗(n, Sr) = (r + ...
متن کاملCharacterization of Cobweb Posets as KoDAGs
The characterization of the large family of cobweb posets as DAGs and oDAGs is given. The dim 2 poset such that its Hasse diagram coincide with digraf of arbitrary cobweb poset Π is constructed. AMS Subject Classification: 05C20, 05C75, 06A07, 11B39
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: Order
سال: 2014
ISSN: 0167-8094,1572-9273
DOI: 10.1007/s11083-014-9331-y