tuòpūkōngjiān
ㄊㄨㄛˋ ㄆㄨ ㄎㄨㄥ ㄐㄧㄢ
Simplified 拓扑空间
Taivo → Settings → Partner inbox → Make the link. It stays in this browser.
Keep 拓撲空間 and it comes back until you know it.