321 research outputs found
Behind the North-South divide: A decomposition analysis
The paper applies modified Oaxaca-type analyses on the eighteen available waves of the British Household Panel Survey to decompose the wage gap among full time employees from either side of the North-South divide and identify its components that can be attributed to measurable worker- and labour market characteristics, and the part due to differences in the returns to these endowments. Further, by applying Juhn, Murphy and Pierce’s (1991) methodology, it is analysed, how changes in these underlying factors could explain the one quarter decline in the wage gap over the 1991 – 2009 period. The paper confirms the existence of a differential treatment effect by showing that only one fifth of the wage gap can be explained by observable differences. The magnitude of the unexplainable coefficient effect is so large, that the remarkable improvements in Northern occupational structure and human capital levels over the period could only translate into an actual decline in the wage gap, because it coincided with a period of increasing inequality among Northern occupational wage premia, which – as a by-product – increased the average Northern wage and this way counterbalanced the effects of the increasing Southern returns to experience, that alone could have increased the initial pay gap by half.England's North-South divide, regional wage gap, Oaxaca decomposition, Juhn, Murphy and Pierce decomposition, Yun's method
A note on tilted Sperner families with patterns
Let and be two nonnegative integers with and . We call
a \textit{(p,q)-tilted Sperner family
with patterns on [n]} if there are no distinct with:
Long (\cite{L}) proved that the cardinality of a (1,2)-tilted Sperner family
with patterns on is
We improve and generalize this result, and prove that the cardinality of
every ()-tilted Sperner family with patterns on [] is Comment: 8 page
Generalized Tur\'an problems for disjoint copies of graphs
Given two graphs and , the maximum possible number of copies of in
an -free graph on vertices is denoted by . We investigate the
function , where denotes vertex disjoint copies of a fixed
graph . Our results include cases when is a complete graph, cycle or a
complete bipartite graph.Comment: 18 pages. There was a wrong statement in the first version, it is
corrected no
A discrete isodiametric result: the Erd\H{o}s-Ko-Rado theorem for multisets
There are many generalizations of the Erd\H{o}s-Ko-Rado theorem. We give new
results (and problems) concerning families of -intersecting -element
multisets of an -set and point out connections to coding theory and
classical geometry. We establish the conjecture that for such
a family can have at most members
On the size of planarly connected crossing graphs
We prove that if an -vertex graph can be drawn in the plane such that
each pair of crossing edges is independent and there is a crossing-free edge
that connects their endpoints, then has edges. Graphs that admit
such drawings are related to quasi-planar graphs and to maximal -planar and
fan-planar graphs.Comment: Appears in the Proceedings of the 24th International Symposium on
Graph Drawing and Network Visualization (GD 2016
Forbidden subposet problems for traces of set families
In this paper we introduce a problem that bridges forbidden subposet and
forbidden subconfiguration problems. The sets form a
copy of a poset , if there exists a bijection such that for any the relation implies
. A family of sets is \textit{-free} if
it does not contain any copy of . The trace of a family on a
set is .
We introduce the following notions: is
-trace -free if for any -subset , the family
is -free and is trace -free if it is
-trace -free for all . As the first instances of these problems
we determine the maximum size of trace -free families, where is the
butterfly poset on four elements with and determine the
asymptotics of the maximum size of -trace -free families for
. We also propose a generalization of the main conjecture of the area of
forbidden subposet problems
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