Quadtrees are everywhere spatial data exists. Mapping services use quadtree-like tile pyramids to serve map tiles at different zoom levels (Bing's quadkey system, for example, addresses tiles as base-4 paths). Game engines use them for collision detection and visibility culling. Geographic information systems use spatial indexes to store and query spatial datasets. PostGIS uses GiST indexes (R-tree-style) for spatial queries on geometries, while PostgreSQL's core supports quadtree-like SP-GiST indexes for certain data types like points.
美國經濟學家伯納德·雅羅斯（Bernard Yaros）指出，特朗普已經使用1962年《貿易擴展法》（Trade Expansion Act）中的第232條，對包括汽車、鋼鐵和鋁在內的產業實施行業特定關稅，並指出「商務部已對藥品、半導體、關鍵礦產和飛機啟動了第232條調查」。
，详情可参考safew官方下载
[qjoly@fedora]~% rpm-ostree status
3. 数学之美：参数化几何体与克莱因瓶