Optimal estimates on the fundamental spectral gap and eigenvalue ratios of one-dimensional Sturm-Liouville operatorsOptimal estimates on the fundamental spectral gap and eigenvalue ratios of one-dimensional Sturm-Liouville operatorsOptimal estimates on the fundamental spectral gap and eigenvalue ratios of one-dimensional Sturm-Liouville operatorsOptimal estimates on the fundamental spectral gap and eigenvalue ratios of one-dimensional Sturm-Liouville operatorsOptimal estimates on the fundamental spectral gap and eigenvalue ratios of one-dimensional Sturm-Liouville operatorsOptimal estimates on the fundamental spectral gap and eigenvalue ratios of one-dimensional Sturm-Liouville operatorsOptimal estimates on the fundamental spectral gap and eigenvalue ratios of one-dimensional Sturm-Liouville operatorsOptimal estimates on the fundamental spectral gap and eigenvalue ratios of one-dimensional Sturm-Liouville operatorsOptimal estimates on the fundamental spectral gap and eigenvalue ratios of one-dimensional Sturm-Liouville operators