Transfer to characteristic zero of the Jacquet–Mao's metaplectic fundamental lemma

Abstract Jacquet conjectured that globally a cuspidal automorphic representation of $\mathrm{G}\mathrm{L}_r$ should be in the image of the metaplectic correspondence precisely when it is distinguished with respect to a split orthogonal similitude group. Jacquet–Mao have suggested an approach to solve this problem by using ``relative'' traces formula. One of the steps of this approach is the Jacquet–Mao's metaplectic fundamental lemma. The author proved this fundamental lemma for any $r$ in the case of positive characteristic. The aim of this paper is to extend this result to the more general case.