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- Dufwenberg, Martin, et al.
(författare)
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Indirect evolution versus strategic delegation : a comparison of two approaches to explaining economic institutions
- 1998
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Two major methods of explaining economic institutions, namely by strategic choices or through (indirect) evolution, are compared for the case of a homogenous quadratic duopoly market. Sellers either can provide incentives for agents to care for sales, or evolve as sellers who care for sales in addition to profits. The two approaches are conceptually quite different, yet similar in the sense that both allow certain kinds of commitment. We show that when the two models are set up in intuitively comparable ways strategic delegation does not change the market results as compared to the usual duopoly solution, while indirect evolution causes a more competitive behavior. Thus the case at hand underscores the differences between the two approaches in explaining economic institutions.
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| 3. |
- Schütz, Martin, et al.
(författare)
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Integral-direct electron correlation methods
- 1999
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Ingår i: Molecular Physics. - 0026-8976 .- 1362-3028. ; 96:4, s. 719-733
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Tidskriftsartikel (refereegranskat)abstract
- Integral-direct implementations of Moller-Plesset perturbation theory up to fourth order (MP4(SDQ) without triple excitations), quadratic configuration interaction with single and double excitations (QCISD), coupled cluster (CCSD), multiconfiguration self-consistent field (MCSCF), second- and third-order multireference perturbation theory (MRPT2, MRPT3), and internally contracted multireference configuration interaction (MRCI) methods are described. All methods use the same three integral-direct kernels, namely direct calculation of Fock matrices, direct partial integral transformation, and direct evaluation of external exchange matrices. New algorithms for the latter two procedures are proposed and implemented, for which the memory requirement scales only linearly with basis set size. Test calculations with more than 500 basis functions are presented. It is demonstrated that integral prescreening can significantly reduce the scaling of the computational cost with molecular size N. For small polyglycine peptides (Gly)(n) (n = 1-4), we observe a scaling of N-3 for the direct integral transformation (formal scaling N-5), and N-4 for the direct computation of the external exchange matrices (formal scaling N-6).
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