2,322 research outputs found
Ich war bestimmt kein Held die Lebensgeschichte von Tönnies Hellmann ; Hafenarbeiter in Hamburg
No full texts.235-249:Tönnies Hellmann im Gespräch mit Marion Gräfin Dönhoff
The Evolution of R&D Networks
No full textDawid H, Hellmann T. The Evolution of R&D Networks. Journal of Economic Behavior and Organization. 2014;105:158-172.We study the evolution of R&D networks in a Cournot model whererms may lower marginal costs due to bilateral R&D collaborations. Stochastically stable R&D networks exhibit the dominant group architecture, and, contrary to the existing literature, generically unique predictions about the size of the dominant group can be obtained. This size decreases monotonically with respect to the cost of link formation and there exists a lower bound on the size of the dominant group for non-empty networks. Stochastically stable networks are always inefficient and an increase in linking costs has a non-monotone effect on average industry profits
Constructions publiques et programmes édilitaires en Grèce du IIe s. av. J.-C. au Ier s. ap. J.-C., Athènes 14-17 mai 1995
No full textHellmann Marie-Christine. Constructions publiques et programmes édilitaires en Grèce du IIe s. av. J.-C. au Ier s. ap. J.-C., Athènes 14-17 mai 1995. In: Topoi, volume 5/2, 1995. pp. 687-692
Convexity and complementarity in network formation. Implications for the structure of pairwise stable networks
No full textHellmann T. Convexity and complementarity in network formation. Implications for the structure of pairwise stable networks. Working Papers. Institute of Mathematical Economics. Vol 423. Bielefeld: Universität Bielefeld; 2009.This paper studies the properties of convexity (concavity) and strategic complements (substitutes) in network formation and the implications for the structure of pairwise stable networks. First, different definitions of convexity (concavity) in own links from the literature are put into the context of diminishing marginal utility of own links. Second, it is shown that there always exists a pairwise stable network as long as the utility function of each player satisfies convexity in own links and strategic complements. For network societies with a profile of utility functions satisfying concavity in own links and strategic complements, a local uniqueness property of pairwise stable networks is derived. The results do neither require any specification on the utility function nor any other additional assumptions such as homogeneity
Renormalization group, trace anomaly and Feynman-Hellmann theorem
No full textWe show that the logarithmic derivative of the gauge coupling on the hadronic mass and the cosmological constant term of a gauge theory are related to the gluon condensate of the hadron and the vacuum respectively. These relations are akin to Feynman-Hellmann relations whose derivation for the case at hand are complicated by the construction of the gauge theory Hamiltonian. We bypass this problem by using a renormalisation group equation for composite operators and the trace anomaly. The relations serve as possible definitions of the gluon condensates themselves which are plagued in direct approaches by power divergences. In turn these results might help to determine the contribution of the QCD phase transition to the cosmological constant and test speculative ideas
The Hellmann–Feynman theorem, the comparison theorem, and the envelope theory
No full textAbstractThe envelope theory is a convenient method to compute approximate solutions for bound state equations in quantum mechanics. It is shown that these approximate solutions obey a kind of Hellmann–Feynman theorem, and that the comparison theorem can be applied to these approximate solutions for two ordered Hamiltonians
[FE3W3S14]4-, A NOVEL HEXANUCLEAR, PURE BIMETAL-SULFUR CLUSTER WITH FE3(MU-3-S)2 CENTER
No full textMüller A, HELLMANN W, Bögge H, JOSTES R, Römer M, SCHIMANSKI U. [FE3W3S14]4-, A NOVEL HEXANUCLEAR, PURE BIMETAL-SULFUR CLUSTER WITH FE3(MU-3-S)2 CENTER. ANGEWANDTE CHEMIE-INTERNATIONAL EDITION IN ENGLISH. 1982;21(11):860-861
Multilingual linked data
No full textMcCrae J, Moran S, Hellmann S, Brümmer M. Multilingual linked data. Semantic Web. 2015;6(4):315-317
Multilingual Linked Open Data (MLOD) 2012 Data Post Proceedings
No full textMcCrae J, Moran S, Hellmann S, Brümmer M, eds. Multilingual Linked Open Data (MLOD) 2012 Data Post Proceedings. Semantic Web. 2015;6(4)
Altruistic Giving Toward Refugees: Identifying Factors That Increase Citizens’ Willingness to Help
No full textFurther materials, data an analyses files for:
Hellmann, D.M., Fiedler, S. & Glöckner, A. (2021). Altruistic Giving Toward Refugees: Identifying Factors That Increase Citizens’ Willingness to Help. Front. Psychol. 12:689184. doi: 10.3389/fpsyg.2021.68918
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