8 research outputs found
Forking in pregeometries.
No full textAbstract: "The aim of this paper is to make progress towards a geometric model theory for non first order theories. The main difficulty is to work in an environment where the compactness theorem fails. This paper continues the work started in [GrLe1]. The main result is an axiomatic approach to the Hrushovski-Zilber group configuration theorem.
Ranks and pregeometries in finite diagrams
No full textAbstract: "The study of classes of models of a finite diagram was initiated by S. Shelah in 1969. A diagram D is a set of types over the empty set, and the class of models of the diagram D consists of the models of T which omit all the types not in D. In this work, we introduce a natural dependence relation on the subsets of the models for the N₀-stable case which share many of the formal properties of forking. This is achieved by considering a rank for this framework which is bounded when the diagram D is N₀-stable. We can also obtain pregeometries with respect to this dependence relation. The dependence relation is the natural one induced by the rank, and the pregeometries exist on the set of realizations of types of minimal rank. Finally, these concepts are used to generalize many of the classical results for models of a totally transcendental first-order theory. In fact, strong analogies arise: models are determined by their pregeometries or their relationship with their pregeometries; however the proofs are different, as we do not have compactness. This is illustrated with positive results (categoricity) as well as negative results (construction of nonisomorphic models).
Shelah's stability spectrum and homogeneity spectrum in finite diagrams
No full textAbstract: "We present Saharon Shelah's Stability Spectrum and Homogeneity Spectrum theorems, as well as the equivalence between the order property and instability in the framework of Finite Diagrams. Finite Diagrams is a context which generalizes the first order case. Localized versions of these theorems are presented. Our presentation is based on several papers; the point of view is contemporary and some of the proofs are new. The treatment of local stability in Finite Diagrams is new.
Forking in pregeometries.
No full textAbstract: "The aim of this paper is to set the foundation to separate geometric model theory from model theory. Our thesis is that it is possible to lift results from geometric model theory to non first order logic (e.g. L[subscript omegaΓéü, omega]). We introduce a relation between subsets of a pregeometry and show that it satisfies all the formal properties that forking satisfies in simple first order theories. This is important when one is trying to lift forking to nonelementary classes, in contexts where there exists pregeometries but not necessarily a well-behaved dependence relation (see for example [HySh]). We use these to reproduce S. Buechler's characterization of local modularity in general. These results are used by Lessmann to prove an abstract group configuration theorem in [Le2].
Remarks on local stability and the local order property
No full textAbstract: "We continue the study of stability of a type in several directions: (1) Inside a fixed model, (2) for classes of models where the compactness theorem fails and (3) for the first order case. Appropriate localizations of the order property, the independence property, and the strict order property are introduced. We are able to generalize some of the results that were known in the case of local stability for the first order theories, and for stability for nonelementary classes (existence of indiscernibles, existence of averages, stability spectrum, equivalence between order and instability). In the first order case, we also prove the local version of Shelah's Trichotomy Theorem. Finally as an application, we give a new characterization of stable types when the ambient first order theory is simple.
Studies on the Oxidation-Reduction Potential and the Bilirubin Deposition of Skin in Jaundiced Patients Part II. Studies on the Bilirubin Deposition of Skin in Jaundiced Patients
No full textWith the purpose to clarify the deposited region of bilirubin and the cause of green tone in the skin of jaundiced patients, the author made the histochemical observation, employing the frezing-drying and also made the observation on the stainability of both fibers, being chiefly composed by collagen and elastoid, to the serum of jaundiced patient and various bilibubin solutions in vitro, using the tail's tendon of young white rat. And the results were as follows. 1. The author applied the freezing-drying to the histochemical studies on the skin stained by bilirubin and got the satisfactory results. 2. As for the staining condition of bilirubin in the skin of jaundiced patient, it was diffuse, but not the paticular region or fiber. 3. Staining the fiber, being chiefly composed by collagen and elastoid, by each solution of cristallin bilirubin, bilirubin soda salt, natural salt-form and ester-form bilirubin and serum of jaundiced patients in the buffer solutions with various pH value, the stainability was the best on the use of ester-form bilirubin and the best pH value was 7.0, and the deposited bilurbin was easily changed to biliverdin on the shift of pH to alkaline side. 4. Staining the above both fibers by biliverdin as same as bilirubin, it's staining deposition was the same degree with that of bilirubin. 5. Therefore, the staining deposition of skin in jaundice was not in the elastin of elastic fiber as put forward by F. Rosenthal, it was diffusely seen in the whole of skin and it was rather strong in the collagenous fiber than elastoid. Shifting the pH of skin to akaline side, the deposited bilirubin was easlly changed to biliverdin and Verdinikterus was occured from it
A primer of simple theories
No full textAbstract: "We present a self-contained exposition of the basic aspects of simple theories while developing the fundamentals of forking calculus. We expound most of the deeper aspects of S. Shelah's 1980 paper Simple unstable theories. The concept of weak dividing has been replaced with that of forking. The exposition is from a contemporary perspective and takes into account contributions due to E. Hrushovski, B. Kim, and A. Pillay.
Colletes yanruae Niu, Zhu & Kuhlmann, In 2013
No full textColletes yanruae Niu, Zhu & Kuhlmann, 2013 (Figs 2–11) Colletes yanruae Niu, Zhu & Kuhlmann, In: Niu et al., 2013b: 114 (female). Diagnosis. Like the female, the male C. yanruae has narrow apical tergal hair bands (Figs 6–7) and much long hair on the scutum (Fig. 5). The male has a very large and broad S7 (Figs 10–11) that is similar in shape to that of C. reinigi Noskiewicz, C. luzhouensis Kuhlmann and C. linzhiensis Niu, Zhu & Kuhlmann. But C. yanruae differs from C. reinigi by the finer and denser punctation of terga, the rounded outer apical corners of S7 (shallowly incised in C. reinigi) and the rounded gonostylus (pointed in C. reinigi), and from C. linzhiensis by the distinctly narrower apical tergal hair bands and shorter malar area (Fig. 4). In C. yanruae , the gonostylus is broader than long, while it is narrower at its base and, thus, longer than broad in C. luzhouensis (Fig. 9). The males of both species are otherwise very similar, with only subtle differences in tergal punctation (punctures of T2 only slightly smaller than on T 1 in C. luzhouensis while in C. yanruae punctures of T2 are about half the diameter of those on T1). The male of C. brumalis Noskiewicz is unknown but likely has distinctly broader apical tergal hair bands than C. yanruae, for the female of C. brumalis Noskiewicz with broader apical tergal hair bands than C. yanruae. Description. Male, BL= 9.5 mm (Fig. 2); head broader than long (Fig. 3), HW: HL= 53: 44; gena slightly narrower than eye in lateral view, GW: EW = 9: 12 (Fig. 4); width of metasoma as broad as that between tegulae, MtW: TW = 52: 52. Clypeus slightly convex, median part with fine oblique spine-shaped punctation (Fig. 3); antenna short, extending to the middle of scutellum, first flagellomere slightly longer than broad, 0.7 time as long as second flagellomere, flagellomeres 2–11 longer than broad, nearly 1.5 times as long as broad and nearly equal to each other in length; malar area medially shorter than width of mandible base, about 1/2 long as width of mandible base; facial fovea shallow and narrow, only half as wide as antennal flagellum; vertex behind eye rounded; propodeum laterally covered with sparse long erect hairs, integumental sculpture completely visible; disc of scutum shiny, with dense punctation, i = 0.5–1.5d (Fig. 5); metasomal terga with apical hair bands, the band on T1 slightly narrower medially, that on T2–T5 nearly 1/6 width as that of the related exposed terga (Fig. 6); posterior margin of T1 translucent and orange, punctation on disc of T1 round and dense, i = 0.2–0.5d (Fig. 7); sloping anterior and lateral anterior parts of T1 covered with erect long plumose hairs, and disc of T1 also with erect long sparse plumose hairs (Fig. 7); apical lobe of S7 large and broad, outer apical corner rounded, but with inside concave below the apical corner (Fig. 10); genitalia as showing in Fig. 8 and Fig. 9, gonostylus short and broad at its base. Antennal flagellum ventrally black; all legs black. Face covered with dense long paler white plumose hairs, intermixed with black plumose hairs; gena, scutellum and mesepisternum covered with long paler white plumose hairs; scutum covered with dense long paler white plumose hairs, intermixed with black plumose hairs (Figs 4–5). Material examined. China, Yunnan, Zhaotong City, Qiaojia County, Yaoshan Town (27º12′N, 103º06′E), 7♀ 1♂ (from Cotoneaster subadpressus), 1♀ (from Berberis sp.), 7.V.2015, leg. Zongxin Ren, Zhibin Tao. Type Materials. Holotype. ♀, China, Yunnan, Lijiang, Yulong Shan (100º18′E, 27º06′N; elev. 2850 m), 19.VII. 1984, leg. Changfang Li; Paratypes. 3♀, China, Yunnan, Lijiang, Yulong Shan (100º18′E, 27º06′N; elev. 2850 m), 17.VII. 1984, leg. Changfang Li; 2♀, China, Yunnan, Lijiang, Baishui (103º54′E, 24º30′N; elev. 3200 m), 17.VII.1984, leg. Jianguo Fan. Distribution. China (Yunnan). Floral associations. Berberis sp. (Berberidaceae), Cotoneaster subadpressus (Rosaceae). Funding This work was supported mainly by the National Specific Research Funds for Public Benefit Department (Agriculture) (201303108) to Zeqing Niu, the NSFC Program J1211002, and the grant (Y229YX5105) from Key Laboratory of Zoological Systematics and Evolution, Chinese Academy of Sciences. Acknowledgements The authors thank Dr. Michael Khulmann, who collaborated with us in studying Chinese Colletes. The authors sincerely thank Dr. Victor H. Gonzalez, Prof. Yanru Wu, Dr. Yanzhou Zhang, Dr. Fuqiang Chen and two anonymous reviewers for their comments and suggestions on earlier drafts of the manuscript, and are grateful to Dr. Douglas Chesters for revising the English language in parts of the manuscript. The authors also wish to thank Ms. Qingyan Dai, who helped to sequence bee samples, and to thank Ms. Huanxi Cao, who helped to re-construct maximum parsimony trees.Published as part of Niu, Zeqing, Ren, Zongxin & Zhu, Chaodong, 2016, Discovery of the male of Colletes yanruae from Yunnan, China (Hymenoptera: Apoidea: Colletidae), pp. 286-293 in Zoological Systematics 41 (3) on pages 290-293, DOI: 10.11865/zs.201630, http://zenodo.org/record/536469
