{"id":"symmetry-is-both-simplifier-and-routing-enabler","text":"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.","truth_value":"IN","source":"","source_url":"","source_hash":"","justifications":[{"type":"SL","antecedents":["symmetry-simplifies-across-graph-domains","social-systems-combine-symmetric-graphs-and-lightweight-fanout"],"outlist":[],"label":"Symmetry is both a simplification strategy (fewer edge types) and a routing prerequisite (fan-out reaches all parties)"}],"dependents":[],"metadata":{"last_reviewed":"2026-06-06T06:26:57","review_result":"pass"},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"symmetry-is-both-simplifier-and-routing-enabler","truth_value":"IN","reason":"SL justification valid","antecedents":["symmetry-simplifies-across-graph-domains","social-systems-combine-symmetric-graphs-and-lightweight-fanout"],"label":"Symmetry is both a simplification strategy (fewer edge types) and a routing prerequisite (fan-out reaches all parties)"},{"node":"symmetry-simplifies-across-graph-domains","truth_value":"IN","reason":"SL justification valid","antecedents":["symmetric-social-graphs-simplify-visibility","maps-bidirectional-edges-share-data"],"label":"Social graphs and road networks both choose mandatory bidirectionality, trading model expressiveness for implementation simplicity"},{"node":"symmetric-social-graphs-simplify-visibility","truth_value":"IN","reason":"SL justification valid","antecedents":["chat-contacts-always-bidirectional","nearby-friends-friendship-always-symmetric"],"label":"Symmetric graphs eliminate directional visibility checks but prevent asymmetric social models"},{"node":"chat-contacts-always-bidirectional","truth_value":"IN","reason":"premise"},{"node":"nearby-friends-friendship-always-symmetric","truth_value":"IN","reason":"premise"},{"node":"maps-bidirectional-edges-share-data","truth_value":"IN","reason":"premise"},{"node":"social-systems-combine-symmetric-graphs-and-lightweight-fanout","truth_value":"IN","reason":"SL justification valid","antecedents":["symmetric-social-graphs-simplify-visibility","fan-out-write-pushes-references-not-data"],"label":"Symmetric graphs eliminate one-way edge complexity; reference-based fan-out avoids data duplication — together they simplify both the model and the delivery"},{"node":"fan-out-write-pushes-references-not-data","truth_value":"IN","reason":"SL justification valid","antecedents":["chat-fanout-on-write","news-feed-fan-out-write-pushes-ids"],"label":"Reference-based fanout limits write amplification to pointer-sized payloads"},{"node":"chat-fanout-on-write","truth_value":"IN","reason":"premise"},{"node":"news-feed-fan-out-write-pushes-ids","truth_value":"IN","reason":"premise"}]}}