拓扑关系的衰退指拓扑深度的递减，计量从起始轴线到每条目的地轴线的拓扑深度的倒数之和，其中拓扑深度可赋予指数权重。
拓扑关系的衰退
Sources
Dalton, R. C. & Dalton, N. S. (2007) Applying Depth Decay Functions to Apace Syntax Network Graphs. Proceedings of 6th International Space Syntax Symposium, Istanbul. Pp.089-01-14