Holm, D.D.; Ivanov, R.I.
(Symmetry, Integrability and Geometry: Methods and Applications, 2013)
A G-strand is a map g: R×R→G for a Lie group G that follows from Hamilton's principle for a certain class of G-invariant Lagrangians. Some G-strands on finite-dimensional groups satisfy 1+1 space-time evolutionary equations ...