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    Genus two mutant knots with the same dimension in knot Floer and Khovanov homologies

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    We exhibit an infinite family of knots with isomorphic knot Heegaard Floer homology. Each knot in this infinite family admits a nontrivial genus two mutant which shares the same total dimension in both knot Floer homology and Khovanov homology. Each knot is distinguished from its genus two mutant by both knot Floer homology and Khovanov homology as bigraded groups. Additionally, for both knot Heegaard Floer homology and Khovanov homology, the genus two mutation interchanges the groups in δ\delta-gradings kk and k-k.Comment: Information about δ\delta-graded homology has been changed along with statement of Theorem 1 and Table 1. Significant changes to Section

    Surgery on links of linking number zero and the Heegaard Floer dd-invariant

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    We study Heegaard Floer homology and various related invariants (such as the hh-function) for two-component L-space links with linking number zero. For such links, we explicitly describe the relationship between the hh-function, the Sato-Levine invariant and the Casson invariant. We give a formula for the Heegaard Floer dd-invariants of integral surgeries on two-component L-space links of linking number zero in terms of the hh-function, generalizing a formula of Ni and Wu. As a consequence, for such links with unknotted components, we characterize L-space surgery slopes in terms of the ν+\nu^{+}-invariants of the knots obtained from blowing down the components. We give a proof of a skein inequality for the dd-invariants of +1+1 surgeries along linking number zero links that differ by a crossing change. We also describe bounds on the smooth four-genus of links in terms of the hh-function, expanding on previous work of the second author, and use these bounds to calculate the four-genus in several examples of links.Comment: This version accepted for publication in Quantum Topolog

    Observational Tests of the Properties of Turbulence in the Very Local Interstellar Medium

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    The Very Local Interstellar Medium (VLISM) contains clouds which consist of partially-ionized plasma. These clouds can be effectively diagnosed via high resolution optical and ultraviolet spectroscopy of the absorption lines they form in the spectra of nearby stars. Among the information provided by these spectroscopic measurements are the root-mean-square velocity fluctuation due to turbulence in these clouds and the ion temperature, which may be partially determined by dissipation of turbulence. We consider whether this turbulence resembles the extensively studied and well-diagnosed turbulence in the solar wind and solar corona. Published observations are used to determine if the velocity fluctuations are primarily transverse to a large-scale magnetic field, whether the temperature perpendicular to the large scale field is larger than that parallel to the field, and whether ions with larger Larmor radii have higher temperatures than smaller gyroradius ions. Although a thorough investigation of the data is underway, a preliminary examination of the published data shows neither evidence for anisotropy of the velocity fluctuations or temperature, nor Larmor radius-dependent heating. These results indicate differences between solar wind and Local Cloud turbulence.Comment: Paper submitted to Nonlinear Processes in Geophysic
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