197,789 research outputs found
Efficient Compilation of a Class of Variational Forms
We investigate the compilation of general multilinear variational forms over
affines simplices and prove a representation theorem for the representation of
the element tensor (element stiffness matrix) as the contraction of a constant
reference tensor and a geometry tensor that accounts for geometry and variable
coefficients. Based on this representation theorem, we design an algorithm for
efficient pretabulation of the reference tensor. The new algorithm has been
implemented in the FEniCS Form Compiler (FFC) and improves on a previous
loop-based implementation by several orders of magnitude, thus shortening
compile-times and development cycles for users of FFC.Comment: ACM Transactions on Mathematical Software 33(3), 20 pages (2007
Elaboration on Two Points Raised in ``Classifier Technology and the Illusion of Progress''
Comment: Elaboration on Two Points Raised in ``Classifier Technology and the
Illusion of Progress'' [math.ST/0606441]Comment: Published at http://dx.doi.org/10.1214/088342306000000033 in the
Statistical Science (http://www.imstat.org/sts/) by the Institute of
Mathematical Statistics (http://www.imstat.org
The Hidden Premise in the Causal Argument for Physicalism
The causal argument for physicalism is anayzed and it's key premise--the causal closure of physics--is found wanting. Therefore, a hidden premise must be added to the argument to gain its conclusion, but the hidden premise is indistinguishable from the conclusion of the causal argument. Therefore, it begs the question on physicalism
Carbon leakage: Grandfathering as an incentive device to avert relocation
Emission allowances are often distributed for free in an early phase of a cap-and-trade scheme (grandfathering) to reduce adverse effects on the profitability of firms. If the grandfathering scheme is phased out over time, firms may nevertheless relocate to countries with a lower carbon price once the competitive disadvantage of their home industry becomes sufficiently high. We show that this is not necessarily the case. A temporary grandfathering policy can be a sufficient instrument to avert relocation in the long run, even if immediate relocation would be profitable in the absence of grandfathering. A necessary condition for this is that the permit price triggers investments in low-carbon technologies or abatement capital
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