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arXiv 1202.5795math.LO
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依赖的梦:叙述类型

Dependent dreams: recounting types

Saharon Shelah

摘要:

我们研究了一般相依理论的模型类。我们继续数学。LO/0702292特别是调查所谓的“类型分解”;论文是什么成立稳定的理论和Th(Q,<)成立依赖的理论。另一种说法是:我们必须考虑足够小的邻域,并使用合理的可定义类型来分析类型。我们注意到,在没有读数的情况下,结果不稳定。首先,与“稳定性谱”平行的是“类型的重新叙述”,即假设lambda = lambda^{< lambda}足够大,M是基数为lambda的T的饱和模型,设粗体S_{aut}(M)是M上直到共轭的完全类型的数量,即当M的某个自同构将p映射到q时,我们标识p,q。而对于独立的T,这个数是2 ^lambda,对于相关的T,这个数是<= lambda,而且它是<=|阿尔法|当lambda = aleph_alpha时,为^{ |T| }。第二,对于稳定的理论,“存在大量的不可分辨性”,一个“太好的不可分辨存在定理”说,例如,如果类型tp(d_beta ; {d_beta:beta < alpha})对于alpha < kappa = cf(kappa)和kappa > 2^{ |T| }是递增的,那么<d_alpha:alpha in S>对于某个稳定的S子集k是不可分辨的。第三,对于稳定的T,一个模型是kappa饱和的当且仅当它是aleph_epsilon饱和的,并且基数< kappa的每一个无限不可分辨的(元素)集都可以增加。我们在这里证明一个类比。第四,对于S(M)中的p,M的外部可定义子集上扩展p的超滤子的数目有一个绝对界2^{ |T| }。将我们自己限制在一个phi(x,y),这个数是有限的,有一个绝对值(取决于T和phi)。

英文摘要:

We investigate the class of models of a general dependent theory. We continue math.LO/0702292 in particular investigating so called "decomposition of types"; thesis is that what holds for stable theory and for Th(Q,<) hold for dependent theories. Another way to say this is: we have to look at small enough neighborhood and use reasonably definable types to analyze a type. We note the results understable without reading. First, a parallel to the "stability spectrum", the "recounting of types", that is assume lambda = lambda^{< lambda} is large enough, M a saturated model of T of cardinality lambda, let bold S_{aut}(M) be the number of complete types over M up to being conjugate, i.e. we identify p,q when some automorphism of M maps p to q . Whereas for independent T the number is 2^lambda, for dependent T the number is <= lambda moreover it is <= | alpha |^{|T|} when lambda = aleph_alpha. Second, for stable theories "lots of indiscernibility exists" a "too good indiscernible existence theorem" saying, e.g. that if the type tp (d_beta ; {d_beta : beta < alpha}) is increasing for alpha < kappa = cf(kappa) and kappa > 2^{|T|} then <d_alpha : alpha in S> is indiscernible for some stationary S subseteq kappa. Third, for stable T,a model is kappa-saturated iff it is aleph_epsilon-saturated and every infinite indiscernible set (of elements) of cardinality < kappa can be increased. We prove here an analog. Fourth, for p in S(M), the number of ultrafilters on the outside definable subsets of M extending p has an absolute bound 2^{|T|} . Restricting ourselves to one phi(x, y), the number is finite, with an absolute found (well depending on T and phi).

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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