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Noam Shalev

Publications and source records attributed to Noam Shalev.

2 recordsLinked to original sources

Shape-Transition in Non-Euclidean Ribbons

Ribbons are thin elastic bodies whose thickness $t$ is much smaller than their width $w$, which is in turn much smaller than their length. Starting from a three-dimensional model, we derive a one-dimensional limit theory for ribbons with rough prestrain, by means of $\Gamma$-convergence. Our model shows that for narrow ribbons, the energy minimizer coincides with the reference (effective) second fundamental form along the midline, while for wide ribbons this is generically not the case. This proves the existence of shape-transitions in such ribbons, as observed in many experiments, generalizing recent results by Maor & Mora to rough prestrains, which more accurately model many of the relevant physical systems. Our analysis combines techniques from the study of Euclidean ribbons due to Freddi et al., the work of Schmidt on dimension reduction of prestrained plates, and a new structure theorem on the scaled limiting strain due to Maor & Mora.

math.AP

Closed-form evaluations of log-sine integrals and Ap\'ery-like sums in terms of polylogarithms

We present a new systematic method for evaluating generalized log-sine integrals in terms of polylogarithms. Our approach is based on an identity connecting ordinary generating functions of polylogarithms to integrals involving the sine function. This method provides closed-form expressions for log-sine integrals of weight up to 4 using only classical polylogarithms, while higher weights require Nielsen polylogarithms. Later we generalize this identity and show how it gives rise to numerous Ap\'ery-like formulae extending results of Koecher, Leshchiner and others. We also derive hyperbolic analogues and recover several functional equations between Nielsen polylogarithms. In the process, we derive new parametric identities similar to those given by Saha and Sinha.

math.NT