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Abstract SupposeKis a knot in a 3-manifoldY, and thatYadmits a pair of distinct contact structures. Assume thatKhas Legendrian representatives in each of these contact structures, such that the corresponding Thurston-Bennequin framings are equivalent. This paper provides a method to prove that the contact structures resulting from Legendrian surgery along these two representatives remain distinct. Applying this method to the situation where the starting manifold is$$-\Sigma(2,3,6m+1)$$ $-\Sigma (2,3,6m+1)$and the knot is a singular fiber, together with convex surface theory we can classify the tight contact structures on certain families of Seifert fiber spaces. 

We identify the motivicKGL/2-local sphere as the fiber of\psi^{3}-1on(2,\eta)-completed HermitianK-theory, over any base scheme containing1/2. This is a motivic analogue of the classical resolution of theK(1)-local sphere, and extends to a description of theKGL/2-localization of an arbitrary motivic spectrum. Our proof relies on a novel conservativity argument that should be of broad utility in stable motivic homotopy theory. 

abstract: In the early 1940s, P. A. Smith showed that if a finite $$p$$-group $$G$$ acts on a finite dimensional complex $$X$$ that is mod $$p$$ acyclic, then its space of fixed points, $X^G$, will also be mod $$p$$ acyclic. In their recent study of the Balmer spectrum of equivariant stable homotopy theory, Balmer and Sanders were led to study a question that can be shown to be equivalent to the following: if a $$G$$-space $$X$$ is a equivariant homotopy retract of the $$p$$-localization of a based finite $$G$$-C.W. complex, given $H 

We describe how power operations descend through homotopy limit spectral sequences. We apply this to describe how norms appear in the $C_2$-equivariant Adams spectral sequence, to compute norms on ${\mathrm{\pi <\#comment/>}}_0$of the equivariant $KU$-local sphere, and to compute power operations for the $K\left(1\right)$-local sphere. An appendix contains material on equivariant Bousfield localizations which may be of independent interest. 

Regulatory networks depict promoting or inhibiting interactions between molecules in a biochemical system. We introduce a category-theoretic formalism for regulatory networks, using signed graphs to model the networks and signed functors to describe occurrences of one network in another, especially occurrences of network motifs. With this foundation, we establish functorial mappings between regulatory networks and other mathematical models in biochemistry. We construct a functor from reaction networks, modeled as Petri nets with signed links, to regulatory networks, enabling us to precisely define when a reaction network could be a physical mechanism underlying a regulatory network. Turning to quantitative models, we associate a regulatory network with a Lotka-Volterra system of differential equations, defining a functor from the category of signed graphs to a category of parameterized dynamical systems. We extend this result from closed to open systems, demonstrating that Lotka-Volterra dynamics respects not only inclusions and collapsings of regulatory networks, but also the process of building up complex regulatory networks by gluing together simpler pieces. Formally, we use the theory of structured cospans to produce a lax double functor from the double category of open signed graphs to that of open parameterized dynamical systems. Throughout the paper, we ground the categorical formalism in examples inspired by systems biology.