Based on ab initio calculations, we quantify the magnetic
couplings and the stress tensor in ferromagnetic Sr-doped LaMnO3 upon combined application of built-in epitaxial and external uniaxial strains. We suggest YAlO3 as a substrate suited to change magnetic order in manganite film with practicable external strains. The effect could lead
to strain-activated switches based on piezoelectric-piezomagnetic heterojunctions. 相似文献
Rhenium does the job! A readily available rhenium complex efficiently catalyzed the direct Meyer–Schuster‐like rearrangement of different alkyl‐ and aryl‐substituted propargylic secondary and tertiary alcohols to the corresponding α,β‐unsaturated compounds, which were produced with virtually complete E stereoselectivity. The reaction proceeded under neutral conditions and no racemization of potentially enolizable stereocenters was observed.
We calculate the small quantum orbifold cohomology of arbitrary weighted projective spaces. We generalize Givental’s heuristic
argument, which relates small quantum cohomology to S1-equivariant Floer cohomology of loop space, to weighted projective spaces and use this to conjecture an explicit formula
for the small J-function, a generating function for certain genus-zero Gromov–Witten invariants. We prove this conjecture using a method
due to Bertram. This provides the first non-trivial example of a family of orbifolds of arbitrary dimension for which the
small quantum orbifold cohomology is known. In addition we obtain formulas for the small J-functions of weighted projective complete intersections satisfying a combinatorial condition; this condition naturally singles
out the class of orbifolds with terminal singularities. 相似文献
In this work we study the global regularity of the free boundaries arising in the optimal partial transport problem. Assuming
the supports of both the source and the target measure to be convex, we show that the free boundaries of the active regions
are globally C0,1/2.
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I propose three equivalent conjectures on the birational geometry of Fano 3-folds. Roughly speaking, they suggest that ergodic,
or chaotic, behaviour does not occur for Fano 3-folds. 相似文献
A group is called extended residually finite (ERF) if every subgroup is closed in the profinite topology. The ERF-property is studied for nilpotent groups, soluble groups, locally finite groups and FC-groups. A complete characterization is given of FC-groups which are ERF. 相似文献
We prove C1 regularity of c-convex weak Alexandrov solutions of a Monge–Ampère type equation in dimension two, assuming only a bound from above on the
Monge–Ampère measure. The Monge–Ampère equation involved arises in the optimal transport problem. Our result holds true under
a natural condition on the cost function, namely non-negative cost-sectional curvature, a condition introduced in Ma et al. (Arch Ration Mech Anal 177(2):151–183, 2005), that was shown in Loeper (Acta Math,
to appear) to be necessary for C1 regularity. Such a condition holds in particular for the case “cost = distance squared” which leads to the usual Monge–Ampère
equation det D2u = f. Our result is in some sense optimal, both for the assumptions on the density [thanks to the regularity counterexamples of
Wang (Proc Am Math Soc 123(3):841–845, 1995)] and for the assumptions on the cost-function [thanks to the results of Loeper
(Acta Math, to appear)]. 相似文献
Whereas geometrical oppositions (logical squares and hexagons) have been so far investigated in many fields of modal logic
(both abstract and applied), the oppositional geometrical side of “deontic logic” (the logic of “obligatory”, “forbidden”,
“permitted”, . . .) has rather been neglected. Besides the classical “deontic square” (the deontic counterpart of Aristotle’s
“logical square”), some interesting attempts have nevertheless been made to deepen the geometrical investigation of the deontic
oppositions: Kalinowski (La logique des normes, PUF, Paris, 1972) has proposed a “deontic hexagon” as being the geometrical
representation of standard deontic logic, whereas Joerden (jointly with Hruschka, in Archiv für Rechtsund Sozialphilosophie
73:1, 1987), McNamara (Mind 105:419, 1996) and Wessels (Die gute Samariterin. Zur Struktur der Supererogation, Walter de Gruyter,
Berlin, 2002) have proposed some new “deontic polygons” for dealing with conservative extensions of standard deontic logic
internalising the concept of “supererogation”. Since 2004 a new formal science of the geometrical oppositions inside logic
has appeared, that is “n-opposition theory”, or “NOT”, which relies on the notion of “logical bi-simplex of dimension m” (m = n − 1). This theory has received a complete mathematical foundation in 2008, and since then several extensions. In this paper,
by using it, we show that in standard deontic logic there are in fact many more oppositional deontic figures than Kalinowski’s
unique “hexagon of norms” (more ones, and more complex ones, geometrically speaking: “deontic squares”, “deontic hexagons”,
“deontic cubes”, . . ., “deontic tetraicosahedra”, . . .): the real geometry of the oppositions between deontic modalities
is composed by the aforementioned structures (squares, hexagons, cubes, . . ., tetraicosahedra and hyper-tetraicosahedra),
whose complete mathematical closure happens in fact to be a “deontic 5-dimensional hyper-tetraicosahedron” (an oppositional
very regular solid).
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