@Article{JPDE-25-41,
author = {Howison , S. D.Lacey , A. A. and Ockendon , J. R.},
title = {Partial Differential Equations That Are Hard to Classify},
journal = {Journal of Partial Differential Equations},
year = {2012},
volume = {25},
number = {1},
pages = {41--65},
abstract = {<p>Semi-linear n×n systems of the form A∂u/∂x+B∂u/∂y=f can generally be solved, at least locally, provided data are imposed on non-characteristic curves. There are at most n characteristic curves and they are determined by the coefficient matrices on the left-hand sides of the equations. We consider cases where such problems become degenerate as a result of ambiguity associated with the definition of characteristic curves. In such cases, the existence of solutions requires restrictions on the data and solutions might not be unique.</p>},
issn = {2079-732X},
doi = {https://doi.org/10.4208/jpde.v25.n1.4},
url = {http://global-sci.org/intro/article_detail/jpde/5174.html}
}