论文标题
围栏，终点和投射的fraïssé理论
Fences, their endpoints, and projective Fraïssé theory
论文作者
论文摘要
我们介绍了一类新的紧凑型Metrizable空间，我们称之为围栏及其光滑的围栏子类。我们隔离了两个家庭$ \ MATHCAL F，\ MATHCAL F_0 HASSE图表的有限部分订单，并表明光滑的围栏正是由$ \ Mathcal f_0 $近似的空间。我们研究了有限部分订单的Hasse图的组合特性，并表明$ \ Mathcal f，\ Mathcal F_0 $是具有共同投影的Fraïssé限制的投射fraïssé家族。我们研究了这个极限，并将获得的光滑围栏描述为其商，我们称之为fraïssé围栏。我们表明，Fraïssé围栏是一个高度同质的空间，它与Lelek风扇具有多个功能，我们检查了其端点空间的结构。在途中，我们在投影式的Fraïssé理论中建立了一些新事实。
We introduce a new class of compact metrizable spaces, which we call fences, and its subclass of smooth fences. We isolate two families $\mathcal F, \mathcal F_0$ of Hasse diagrams of finite partial orders and show that smooth fences are exactly the spaces which are approximated by projective sequences from $\mathcal F_0$. We investigate the combinatorial properties of Hasse diagrams of finite partial orders and show that $\mathcal F, \mathcal F_0$ are projective Fraïssé families with a common projective Fraïssé limit. We study this limit and characterize the smooth fence obtained as its quotient, which we call a Fraïssé fence. We show that the Fraïssé fence is a highly homogeneous space which shares several features with the Lelek fan, and we examine the structure of its spaces of endpoints. Along the way we establish some new facts in projective Fraïssé theory.
