Status: IN
Bidirectional symmetry serves a dual architectural role: it simplifies reasoning across both social and spatial graph domains (eliminating one-way edge complexity) and specifically enables complete lightweight write-time routing in social systems through reference-based fan-out.
Symmetry is both a simplification strategy (fewer edge types) and a routing prerequisite (fan-out reaches all parties)
Depends on (SL): symmetry-simplifies-across-graph-domains, social-systems-combine-symmetric-graphs-and-lightweight-fanout