“…It fits very well with the aforementioned work of Lusztig. In positive depth there is the result of Yu [Yu2, §7.10], who proved (1) for unramified tori. For GL n (F ), (1) was claimed in [Yu1,§2.3.6] and proved in [ABPS2,Proposition 4.5]. For GSp 4 (F ), (1) is proved in [Gan,§ 10].…”