Mathematical Research Letters
Volume 12, Issue 6, November 2005 pp. 933-944.
Computing the location and the direction of bifurcationAuthors: Philip Korman (1), Yi Li (2), and Tiancheng Ouyang (3)
Author institution: University of Cincinnati (1), Hunan Normal University (2), and Brigham Young University (3)
Summary: We consider positive solutions of the Dirichlet problem \[ u^{\prime\prime}(x)+\lambda f(u(x))=0 on (-1,1) u(-1)=u(1)=0. \] depending on a positive parameter $\lambda$. Each solution $u(x)$ is an even function, and hence it is uniquely identified by $\alpha=u(0)$. We present a formula, which allows to compute all $\alpha$'s where a turn may occur, and then we give another formula, which allows to compute the direction of the turn. As an application, we present a computer assisted proof of the exact bifurcation diagram in case $f(u)$ is any cubic with real and distinct roots. Another application is a computer assisted proof of a conjecture by S.-H. Wang \cite{W1}, related to gas combustion.
Contents Full-Text PDF