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It is a long standing open problem to find an explicit description of the stable set polytope of claw-free graphs. Yet more than 20 years after the discovery of a polynomial algorithm for the maximum stable set problem for claw-free graphs, there is even no conjecture at hand today. Such a conjecture exists for the class of quasi-line graphs. This class of(More)
The 0/1 primal separation problem is: Given an extreme point ¯ x of a 0/1 polytope P and some point x £ , find an inequality which is tight at ¯ x, violated by x £ and valid for P or assert that no such inequality exists. It is known that this separation variant can be reduced to the standard separation problem for P. We show that 0/1 optimization and 0/1(More)
  • Paolo Ventura, Anna Zeppieri, Italo Mazzitelli, Francesca D’Antona
  • 1998
We present the results of stellar evolutionary computations to study the sensitivity of lithium depletion in models of mass and metallicity close to solar, and its dependence on the micro – macro physical inputs in the models, like thermo-dynamics, mixing, overshooting and the convective model. We find that even marginal chemical inhomogeneities in stellar(More)
Red giants are evolved stars that have exhausted the supply of hydrogen in their cores and instead burn hydrogen in a surrounding shell. Once a red giant is sufficiently evolved, the helium in the core also undergoes fusion. Outstanding issues in our understanding of red giants include uncertainties in the amount of mass lost at the surface before helium(More)
It is a long standing open problem to find an explicit description of the stable set polytope of claw-free graphs. Yet more than 20 years after the discovery of a polynomial algorithm for the maximum stable set problem for claw-free graphs, there is even no conjecture at hand today. Such a conjecture exists for the class of quasi-line graphs. This class of(More)
We present analysis of deep CCD photometry for the very rich, old open star cluster NGC 6819. The science goals are to catalogue the white dwarfs in the cluster and measure the cluster luminosity and mass functions. These CFH12K data results represent the first of nineteen open star clusters which were imaged as a part of the CFHT Open Star Cluster Survey.(More)
The 0/1 primal separation problem is: Given an extreme point <i>x</i> of a 0/1 polytope <i>P</i> and some point <i>x*,</i> find an inequality which is tight at <i>x,</i> violated by <i>x*</i> and valid for <i>P</i> or assert that no such inequality exists. It is known that this separation variant can be reduced to the standard separation problem for(More)
Concurrent hemolysis in patients with vitamin B12 deficiency is a well-recognized phenomenon and has been attributed to intramedullary destruction of erythrocytes (ineffective erythropoiesis). Recent studies revealed that homocysteine increased the risk of hemolysis in vitamin B12 deficiency in vitro and there is a high frequency (30%) of vitamin B12(More)
Received ; accepted In press to ApJ. ABSTRACT Fully evolutionary models have been built to follow the phases of Asymptotic Giant Branch (AGB) evolution with mass loss, for metal mass fractions from Z= 2 × 10 −4 to Z= 4 × 10 −3. The Hot Bottom Burning (HBB) at the base of the convective envelope is followed by fully coupling nuclear burning and non(More)