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921.
922.
It is well known that the size of propositional classical proofs can be huge. Proof-theoretical studies discovered exponential
gaps between cut-free (or normal) proofs and the corresponding (non-normal) proofs with cuts (or modus ponens). The task of
automatic theorem proving is, on the other hand, usually based on the construction of cut-free or only atomic-cuts proofs,
since this procedure produces less alternative choices. There are familiar tautologies whose cut-free proofs are huge while
the non-cut-free ones are small. The aim of this paper is to discuss basic methods of weight and/or size reduction of deductions
by switching from traditional tree-structured deductions to circuit-structured deductions. A desired efficiency is achieved
by adding the standard weakening rule of inference upgraded by adding suitable (propositional) unifications modulo variable
substitutions. We show examples where such a unification provides strong (in fact, exponential) compression of cut-free deductions.
Bibliography: 10 titles.
Published in Zapiski Nauchnykh Seminarov POMI, Vol. 358, 2008, pp. 77–99. 相似文献
923.
924.
C. dos Santos E. da Hora 《The European Physical Journal C - Particles and Fields》2010,70(4):1145-1151
In this paper we study the structure of one dimensional topological solitons in a generalized Abelian-Higgs Chern–Simons model
where the kinetic term is non-canonical. We present an example of an analytical self-dual electrically charged soliton solution
which has a finite momentum per unit length along its direction. We compared the physical properties of our soliton with those
for wall of Jackiw–Lee–Weinberg wall presented in Jackiw et al. (Phys. Rev. D 42:3488, 1990) to conclude that the non-canonical kinetic term can make the wall “thicker” redistributing uniformly the momentum flow along
it. 相似文献
925.
Antonio Gaudiello Rejeb Hadiji 《Calculus of Variations and Partial Differential Equations》2010,39(3-4):593-619
In this paper, starting from the classical 3D micromagnetic energy, we determine, via an asymptotic analysis, the free energy of two joined ferromagnetic thin films. We distinguish different regimes depending on the limit of the ratio between the small thicknesses of the two films. 相似文献
926.
Induced polarization forward modelling using finite element method and the fractal model 总被引:1,自引:0,他引:1
V.J. da C. Farias C.H. de M. Maranhão B.R.P. da Rocha N. de P.O. de Andrade 《Applied Mathematical Modelling》2010
The modeling of induced polarization data from 2D and 3D geological medium was developed. We applied the finite element method and the fractal model to complex resistivity of rocks as an intrinsic electrical property of geological medium. The LU factorization and pre-conditioned complex bi-conjugated gradient method were applied to solve the complex linear equation system. The modeling implemented in this work was efficient and prompt. In addition, the induced polarization survey using the fractal model as intrinsic property of the medium is a promising method for environmental investigation. 相似文献
927.
ZDM – Mathematics Education - Our article aims to show how illuminating mathematical work as a concept from didactics of mathematics is useful in understanding issues relating to proving and... 相似文献
928.
Maria Catarina Coutinho Varela da Silva João Luís Maia Figueirinhas 《Liquid crystals》2016,43(1):124-130
A number of polymer dispersed liquid crystal (PDLC) films based on dimethacrylate monomers were synthesised by polymer-induced phase separation (PIPS) using polyethylene glycol p-(1,1,3,3-tetramethylbutyl)-phenyl ether (TX-100) as an additive up to total solution weight of 10% aiming to modify the initial anchorage force of the liquid crystal (LC) molecules to the polymeric matrix. The effects of the addition of this additive to the PDLC films were studied resorting to electro-optical studies. Using a fitting model, several parameters were correlated such as the permanent memory effect (PME), the voltage required to achieve 90% of maximum transmittance (E90), the average elastic constant (K) and the rotational viscosity of the director (γ). The use of TX-100 results on an increase on the PME and γ, and decrease on the E90 and K. 相似文献
929.
930.
Christina C. Roggatz Mercedes González-Wangüemert Hugo Pereira Maria João Rodrigues Manuela Moreira da Silva Luísa Barreira 《Natural product research》2016,30(18):2034-2040
This work reports for the first time the nutritional profile and antioxidant potential of the edible sea cucumber Holothuria arguinensis from the North-eastern Atlantic. H. arguinensis has high levels of protein, with the amino acids profile dominated by alanine, glycine and proline and low lysine/arginine ratios. Its carbohydrate and energetic contents are also low as well as the total lipid levels, although its lipid profile is rich in polyunsaturated fatty acids (PUFA), especially arachidonic, eicosapentaenoic and docosahexaenoic acids. In addition, H. arguinensis has high levels of calcium. The water and ethanol extracts show ability to scavenge free radicals and to chelate copper and iron ions. Our results indicate that H. arguinensis has a balanced nutritional quality suitable for human consumption. In addition, it contains compounds with antioxidant potential; thus its intake can contribute for a healthy and well-balanced diet. 相似文献