On a conjecture of Faulhuber and Steinerberger on the logarithmic derivative of ${\vartheta }_4$

Anne-Maria Ernvall-Hytönen, Esa V. Vesalainen

Faulhuber and Steinerberger conjectured that the logarithmic derivative of ${\vartheta }_4$ has the property that $y^2{\vartheta }_4^{\prime }(y)/{\vartheta }_4(y)$ is strictly decreasing and stri…