diff --git a/domains/ai-alignment/safe AI development requires building alignment mechanisms before scaling capability.md b/domains/ai-alignment/safe AI development requires building alignment mechanisms before scaling capability.md
index 09030349..02e9cbe0 100644
--- a/domains/ai-alignment/safe AI development requires building alignment mechanisms before scaling capability.md	
+++ b/domains/ai-alignment/safe AI development requires building alignment mechanisms before scaling capability.md	
@@ -21,6 +21,12 @@ This phased approach is also a practical response to the observation that since
 
 Anthropic's RSP rollback demonstrates the opposite pattern in practice: the company scaled capability while weakening its pre-commitment to adequate safety measures. The original RSP required guaranteeing safety measures were adequate *before* training new systems. The rollback removes this forcing function, allowing capability development to proceed with safety work repositioned as aspirational ('we hope to create a forcing function') rather than mandatory. This provides empirical evidence that even safety-focused organizations prioritize capability scaling over alignment-first development when competitive pressure intensifies, suggesting the claim may be normatively correct but descriptively violated by actual frontier labs under market conditions.
 
+
+### Additional Evidence (extend)
+*Source: [[2026-02-00-yamamoto-full-formal-arrow-impossibility]] | Added: 2026-03-12 | Extractor: anthropic/claude-sonnet-4.5*
+
+Arrow's impossibility theorem now has a full formal representation using proof calculus in formal logic (Yamamoto, PLOS One, February 2026). This provides machine-checkable verification of the theorem's validity, strengthening the mathematical foundation for claims that universal alignment faces fundamental impossibility constraints. The formal proof complements existing computer-aided proofs (AAAI 2008) and simplified proofs via Condorcet's paradox, offering a complete logical representation that can be mechanically verified.
+
 ---
 
 Relevant Notes:
diff --git a/inbox/archive/2026-02-00-yamamoto-full-formal-arrow-impossibility.md b/inbox/archive/2026-02-00-yamamoto-full-formal-arrow-impossibility.md
index fe5851b6..13961444 100644
--- a/inbox/archive/2026-02-00-yamamoto-full-formal-arrow-impossibility.md
+++ b/inbox/archive/2026-02-00-yamamoto-full-formal-arrow-impossibility.md
@@ -7,9 +7,14 @@ date: 2026-02-01
 domain: ai-alignment
 secondary_domains: [critical-systems]
 format: paper
-status: unprocessed
+status: enrichment
 priority: medium
 tags: [arrows-theorem, formal-proof, proof-calculus, social-choice]
+processed_by: theseus
+processed_date: 2026-03-11
+enrichments_applied: ["safe AI development requires building alignment mechanisms before scaling capability.md"]
+extraction_model: "anthropic/claude-sonnet-4.5"
+extraction_notes: "Pure formal verification work with no direct AI alignment discussion in the paper itself. Strengthens mathematical foundation for existing Arrow's impossibility claims in the KB. No new claims warranted - this is methodological advancement (formal proof) of an already-established theorem rather than novel insight about alignment."
 ---
 
 ## Content
@@ -30,3 +35,9 @@ Key contribution: meticulous derivation revealing the global structure of the so
 PRIMARY CONNECTION: universal alignment is mathematically impossible because Arrows impossibility theorem applies to aggregating diverse human preferences into a single coherent objective
 WHY ARCHIVED: Provides formal verification foundation for our Arrow's impossibility claim
 EXTRACTION HINT: Likely enrichment to existing claim rather than standalone — add as evidence that Arrow's theorem is now formally machine-verifiable
+
+
+## Key Facts
+- Arrow's impossibility theorem received full formal representation using proof calculus (Yamamoto, PLOS One, February 2026)
+- Formal proof complements existing computer-aided proofs from AAAI 2008
+- Paper provides meticulous derivation revealing global structure of social welfare function central to the theorem