Self-similar smoothing of a discontinuity by degenerate cross-diffusion
Abstract
We consider the dynamics of an idealised cross-diffusion model of biological invasion in which the diffusion of an invading population is inhibited by a resident population, which is in turn degraded by the former. We formulate and numerically solve the problem that describes the self-similar smoothing of an initially piecewise-constant invading population. In the limit the height ahead of the initial discontinuity vanishes, the speed of propagation also vanishes, but only logarithmically slowly. This result is confirmed by a matched asymptotic analysis. The singular nature of this limit indicates that the system does not permit the existence of compactly supported solutions that exhibit a moving front or interface, which has important implications for the simulation of more complex models that also feature this degenerate diffusive mechanism.
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BibTeX
@misc{dallaston2026selfsimilar,
title = {{Self-similar smoothing of a discontinuity by degenerate cross-diffusion}},
author = {Michael C. Dallaston},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2606.15228},
eprint = {2606.15228},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.15228},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Self-similar smoothing of a discontinuity by degenerate cross-diffusion
AU - Michael C. Dallaston
PY - 2026
DA - 2026/08/30
PB - arXiv
DO - 10.48550/arxiv.2606.15228
UR - https://arxiv.org/abs/2606.15228
AB - We consider the dynamics of an idealised cross-diffusion model of biological invasion in which the diffusion of an invading population is inhibited by a resident population, which is in turn degraded by the former. We formulate and numerically solve the problem that describes the self-similar smoothing of an initially piecewise-constant invading population. In the limit the height ahead of the initial discontinuity vanishes, the speed of propagation also vanishes, but only logarithmically slowly. This result is confirmed by a matched asymptotic analysis. The singular nature of this limit indicates that the system does not permit the existence of compactly supported solutions that exhibit a moving front or interface, which has important implications for the simulation of more complex models that also feature this degenerate diffusive mechanism.
ER -