TY - GEN AU - Paliathanasis,Andronikos AU - Leach,P.G.L. TI - Noether's Theorem and Symmetry SN - books978-3-03928-235-7 PY - 2020/// PB - MDPI - Multidisciplinary Digital Publishing Institute KW - n/a KW - integrable nonlocal partial differential equations KW - continuous symmetry KW - Gauss-Bonnet cosmology KW - double dispersion equation KW - optimal systems KW - viscoelasticity KW - group-invariant solutions KW - symmetry reduction KW - Noether symmetries KW - roots KW - modified theories of gravity KW - invariant KW - variational principle KW - action integral KW - conservation laws KW - conservation law KW - Noether operators KW - quasi-Noether systems KW - Noether symmetry approach KW - wave equation KW - Lagrange anchor KW - quasi-Lagrangians KW - Lie symmetry KW - multiplier method KW - analytic mechanics KW - optimal system KW - spherically symmetric spacetimes KW - Boussinesq equation KW - lie symmetries KW - generalized symmetry KW - first integral KW - Noether's theorem KW - Lie symmetries KW - nonlocal transformation KW - energy-momentum tensor KW - boundary term KW - first integrals KW - invariant solutions KW - FLRW spacetime KW - Noether operator identity KW - Kelvin-Voigt equation KW - symmetries KW - partial differential equations KW - systems of ODEs KW - approximate symmetry and solutions N1 - Open Access N2 - In Noether's original presentation of her celebrated theorem of 1918, allowances were made for the dependence of the coefficient functions of the differential operator which generated the infinitesimal transformation of the Action Integral upon the derivatives of the dependent variable(s), the so-called generalized, or dynamical, symmetries. A similar allowance is to be found in the variables of the boundary function, often termed a gauge function by those who have not read the original paper. This generality was lost after texts such as those of Courant and Hilbert or Lovelock and Rund confined attention to only point transformations. In recent decades, this diminution of the power of Noether's Theorem has been partly countered, in particular, in the review of Sarlet and Cantrijn. In this Special Issue, we emphasize the generality of Noether's Theorem in its original form and explore the applicability of even more general coefficient functions by allowing for nonlocal terms. We also look at the application of these more general symmetries to problems in which parameters or parametric functions have a more general dependence upon the independent variables UR - https://mdpi.com/books/pdfview/book/2056 UR - https://directory.doabooks.org/handle/20.500.12854/54710 ER -