排序方式: 共有29条查询结果,搜索用时 15 毫秒
1.
Tapani Hyttinen Saharon Shelah 《Proceedings of the American Mathematical Society》2002,130(10):2837-2843
For suitable groups we will show that one can add a Boolean algebra by forcing in such a way that is almost isomorphic to . In particular, we will give a positive answer to the following question due to J. Roitman: Is a possible number of automorphisms of a rich Boolean algebra?
2.
Tapani Hyttinen 《Archive for Mathematical Logic》1992,31(3):193-199
3.
Based on Crapo's theory of one point extensions of combinatorial geometries, we find various classes of geometric lattices that behave very well from the point of view of stability theory. One of them, , is ω-stable, it has a monster model and an independence calculus that satisfies all the usual properties of non-forking. On the other hand, these classes are rather unusual, e.g. in the Smoothness Axiom fails, and so is not an AEC. 相似文献
4.
We introduce a new approach to the model theory of metric structures by defining the notion of a metric abstract elementary class (MAEC) closely resembling the notion of an abstract elementary class. Further we define the framework of a homogeneous MAEC were we additionally assume the existence of arbitrarily large models, joint embedding, amalgamation, homogeneity and a property which we call the perturbation property. We also assume that the Löwenheim-Skolem number, which in this setting refers to the density character of the set instead of the cardinality, is ${\aleph_0}$ . In these settings we prove an analogue of Morley’s categoricity transfer theorem. We also give concrete examples of homogeneous MAECs. 相似文献
5.
Trying to interpret B. Zilber's project on model theory of quantum mechanics we study a way of building limit models from finite-dimensional approximations. Our point of view is that of metric model theory, and we develop a method of taking ultraproducts of unbounded operators. We first calculate the Feynman propagator for the free particle as defined by physicists as an inner product of the eigenvector of the position operator with eigenvalue and , where is the time evolution operator. However, due to a discretising effect, the eigenvector method does not work as expected, and straightforward calculations give the wrong value. We look at this phenomenon, and then complement this by showing how to instead correctly calculate the kernel of the time evolution operator (for both the free particle and the harmonic oscillator) in the limit model. We believe that our method of calculating these is new. 相似文献
6.
Tapani Hyttinen 《Archive for Mathematical Logic》2000,39(2):89-102
We search for a set-up in which results from the theory of infinite models hold for finite models. As an example we prove
results from stability theory.
Received: 23 February 1998 相似文献
7.
Working with uncountable structures of fixed cardinality, we investigate the complexity of certain equivalence relations and show that if , then many of them are ‐complete, in particular the isomorphism relation of dense linear orders. Then we show that it is undecidable in whether or not the isomorphism relation of a certain well behaved theory (stable, NDOP, NOTOP) is ‐complete (it is, if , but can be forced not to be). 相似文献
8.
Tapani Hyttinen 《Mathematical Logic Quarterly》2002,48(4):533-554
We revisit the theory of amalgamation classes but we do not insist on staying within elementary classes. 相似文献
9.
Taneli?Huuskonen Tapani?Hyttinen Mika?RautilaEmail author 《Archive for Mathematical Logic》2004,43(1):85-120
We show in the paper that for any non-classifiable countable theory T there are non-isomorphic models
and
that can be forced to be isomorphic without adding subsets of small cardinality. By making suitable cardinal arithmetic assumptions we can often preserve stationary sets as well. We also study non-structure theorems relative to the Ehrenfeucht-Fraïssé game.
The research of the first and second author was partially supported by Academy of Finland grant 40734
Mathematics Subject Classification (2000): 03C55, 03C45 相似文献
10.
A Comparative Study of Pyrolysis Liquids by Slow Pyrolysis of Industrial Hemp Leaves,Hurds and Roots
Ayobami Salami Jorma Heikkinen Laura Tomppo Marko Hyttinen Timo Keklinen Janne Jnis Jouko Vepslinen Reijo Lappalainen 《Molecules (Basel, Switzerland)》2021,26(11)
This study assessed the pyrolysis liquids obtained by slow pyrolysis of industrial hemp leaves, hurds, and roots. The liquids recovered between a pyrolysis temperature of 275–350 °C, at two condensation temperatures 130 °C and 70 °C, were analyzed. Aqueous and bio-oil pyrolysis liquids were produced and analyzed by proton nuclear magnetic resonance (NMR), gas chromatography–mass spectrometry (GC-MS), and atmospheric pressure photoionization Fourier transform ion cyclotron resonance mass spectrometry (APPI FT-ICR MS). NMR revealed quantitative concentrations of the most abundant compounds in the aqueous fractions and compound groups in the oily fractions. In the aqueous fractions, the concentration range of acetic acid was 50–241 gL−1, methanol 2–30 gL−1, propanoic acid 5–20 gL−1, and 1-hydroxybutan-2-one 2 gL−1. GC-MS was used to compare the compositions of the volatile compounds and APPI FT-ICR MS was utilized to determine the most abundant higher molecular weight compounds. The different obtained pyrolysis liquids (aqueous and oily) had various volatile and nonvolatile compounds such as acetic acid, 2,6-dimethoxyphenol, 2-methoxyphenol, and cannabidiol. This study provides a detailed understanding of the chemical composition of pyrolysis liquids from different parts of the industrial hemp plant and assesses their possible economic potential. 相似文献