Lean4 proof that SSOT requires definition-time hooks and introspection
Details
- External ID
- 46537459
- Source
- HN
- Company
- —
- Product
- Lean4 proof that SSOT requires definition-time hooks and introspection
- Website domain
- zenodo.org
- Launched
- Jan. 8, 2026
- Cohort
- —
- Upvotes
- 10
- Upvotes percentile
- 0.5006587615283268
- Tags
- —
- Fetched at
- Sept. 7, 2026, 9:25 p.m.
- Updated at
- Sept. 7, 2026, 9:25 p.m.
Description
I formalized the Single Source of Truth (SSOT) principle in Lean 4 (~2.1k LOC, zero sorry) and proved two core results:Structural SSOT is achievable only when a language provides definition-time hooks and runtime introspection. Macros/codegen (before definition) and reflection (after definition) are insufficient. These requirements are derived, not chosen: because structural facts are fixed at definition, derivation must occur at definition time and be introspectable to verify DOF = 1.Would appreciate review, critique, or independent checking of the Lean scripts.
Enrichment
- Theme
- developer tools and programming utilities
- Vertical
- Horizontal
- Function
- Dev tools
- Audience
- Developer
- AI stance
- Not AI
- Project type
- Hobby / open-source project
- Normalized one-liner
- lean4 proof about single source of truth
- Manually corrected
- False
Could you build this?
No Writing 2,100 lines of formal proofs with zero sorrys in Lean 4 requires deep expertise in formal verification, type theory, and mathematical logic that LLMs cannot reliably produce autonomously.
What it would actually take: Developing formal proofs of this scale requires Lean 4 along with deep expertise in formal semantics, epistemic logic, and proof engineering. The creator must translate informal software design principles into rigorous mathematical axioms, formalize structural subtyping and reflection semantics, and construct complex inductive proofs and tactic scripts without logical gaps. Current LLMs frequently hallucinate tactics and fail at sustained non-trivial formal verification.
Discussion
20 comments analyzed.
Concerns raised: Proofs are trivial (just rfl, unfolding definitions), Model doesn't mirror real compiler/language semantics, Definitions chosen to make theorems tautological rather than meaningful, Single author, Zenodo, appears to be AI-generated work (red flags for credibility), Mapping from formal model to real systems requires interpretation, undermines claims
Competitors
Other products that read as similar to this one — 22 launches clear the similarity bar, closest 8 shown.
Attention rank: #13 of 23 (itself plus its competitors, highest first — normalized so YC and Product Hunt are compared fairly).
Launched 24 days after the earliest competitor.
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Other launches for this product
- No other launches for this product.
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