950 research outputs found

    Stationary Points of O'Hara's Knot Energies

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    In this article we study the regularity of stationary points of the knot energies EαE^\alpha introduced by O'Hara in the range α∈(2,3)\alpha \in (2,3). In a first step we prove that EαE^\alpha is C1C^1 on the set of all regular embedded closed curves belonging to H(α+1)/2,2H^{(\alpha +1)/2,2} and calculate its derivative. After that we use the structure of the Euler-Lagrange equation to study the regularity of stationary points of EαE^\alpha plus a positive multiple of the length. We show that stationary points of finite energy are of class C∞C^\infty - so especially all local minimizers of EαE^\alpha among curves with fixed length are smooth.Comment: Corrected typo

    DOES FINITE KNOT ENERGY LEAD TO DIFFERENTIABILITY?

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    New Directions in Geometric and Applied Knot Theory

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    The aim of this book is to present recent results in both theoretical and applied knot theory&#8212which are at the same time stimulating for leading researchers in the &#64257eld as well as accessible to non-experts. The book comprises recent research results while covering a wide range of di&#64256erent sub-disciplines, such as the young &#64257eld of geometric knot theory, combinatorial knot theory, as well as applications in microbiology and theoretical physics

    Logic of Negation-Complete Interactive Proofs (Formal Theory of Epistemic Deciders)

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    We produce a decidable classical normal modal logic of internalised negation-complete and thus disjunctive non-monotonic interactive proofs (LDiiP) from an existing logical counterpart of non-monotonic or instant interactive proofs (LiiP). LDiiP internalises agent-centric proof theories that are negation-complete (maximal) and consistent (and hence strictly weaker than, for example, Peano Arithmetic) and enjoy the disjunction property (like Intuitionistic Logic). In other words, internalised proof theories are ultrafilters and all internalised proof goals are definite in the sense of being either provable or disprovable to an agent by means of disjunctive internalised proofs (thus also called epistemic deciders). Still, LDiiP itself is classical (monotonic, non-constructive), negation-incomplete, and does not have the disjunction property. The price to pay for the negation completeness of our interactive proofs is their non-monotonicity and non-communality (for singleton agent communities only). As a normal modal logic, LDiiP enjoys a standard Kripke-semantics, which we justify by invoking the Axiom of Choice on LiiP's and then construct in terms of a concrete oracle-computable function. LDiiP's agent-centric internalised notion of proof can also be viewed as a negation-complete disjunctive explicit refinement of standard KD45-belief, and yields a disjunctive but negation-incomplete explicit refinement of S4-provability.Comment: Expanded Introduction. Added Footnote 4. Corrected Corollary 3 and 4. Continuation of arXiv:1208.184
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