Life & fun · alternatives · 2026
24 alternatives to Lean4 proof that SSOT requires definition-time hooks and introspection
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.
This Lean 4 formalization demonstrates that achieving Single Source of Truth for structural data requires programming language support for definition-time hooks and runtime introspection. The work proves macros and… Below are 24 products that do a similar job, ranked by how close each is in meaning and then by launch-day votes.
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To my knowledge, this is the first formally verified implementation of a 3D constructive solid geometry (CSG) operation: mesh intersection, implemented in Lean 4 and verified against a concise specification that pins down the surface of the resulting mesh exactly and guarantees practical well-formedness conditions on the triangulation. This project is also an experiment in avoiding having to trust AI-generated code. A human reviewer only needs to read 93 lines of formal specification and run the Lean checker to certify the correctness of the kernel, skipping the intricate 1000+ lines of…
Jul 2026 · github.com · its alternatives →
- 2
This project aims to formalize the first volume of Prof. Bertrand Russell’s Principia Mathematica using the Lean theorem prover. Throughout the formalization, I tried to rigorously follow Prof. Russell’s proof, with no or little added statements from my side, which were only necessary for the formalization but not the logical argument. Should you notice any inaccuracy (even if it does not necessarily falsify the proof), please let me know as I would like to proceed with the same spirit of rigour. Before starting this project, I had already found Prof. Elkind’s formalization of the Principia…
2025 · github.com · its alternatives →
- 3
Framework for specifying and proving properties—such as robustness, fairness, and interpretability—of machine learning models using Lean 4. - fraware/leanverifier
2025 · github.com · its alternatives →
- 4
At Cajal (YC W26) we’re excited to share Talos (https://github.com/cajal-technologies/talos), an open source framework for formal verification of WebAssembly modules in Lean. AI is now writing tons of the code that gets pushed to production. As code generation gets cheaper, verification becomes the bottleneck. We believe in a future where every piece of software comes with a mathematical proof that it does what its author intended - in doing so, eliminating many classes of exploits. Talos is part of the foundation for that. Talos provides a Wasm interpreter optimized for…
Jun 2026 · github.com · its alternatives →
- 5
2017 · craftinginterpreters.com · its alternatives →
- 6
Full-stack CRUD, simplified, with SSOT TypeScript entities - remult/remult
2022 · github.com · its alternatives →
- 7
A Clojure implementation of the logic programming language from chapter 4 of SICP - jdormit/sicp-logic
2019 · github.com · its alternatives →
- 8
2017 · craftinginterpreters.com · its alternatives →
- 9
We've been building Crust (https://crustjs.com/), a TypeScript-first, Bun-native CLI framework with zero dependencies. It's been powering our core product internally for a while, and we're now open-sourcing it. The problem we kept running into: existing CLI frameworks in the JS ecosystem are either minimal arg parsers where you wire everything yourself, or heavyweight frameworks with large dependency trees and Node-era assumptions. We wanted something in between. What Crust does differently: - Full type inference from definitions — args and flags are inferred automatically. No…
Mar 2026 · github.com · its alternatives →
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This project is inspired by some of the asserts in Unreal engine. Due to reliance on core_intrinsics it is necessary to develop using nightly Rust, but there are stubs in place so a production build will not require nightly. I recently released version 0.2 which includes no_std support and adds optional log message arguments to the ensure macro.
2024 · github.com · its alternatives →
- 11
Hi HN, I turned the freshly published paper “The Constructor Theory of Time” by David Deutsch and Chiara Marletto (arXiv, 13 May 2025) into an executable Python library. What you’ll find • One-to-one translation of the paper’s formalism: Substrates, Attributes, Tasks, Constructors, and task-algebra operators • Possibility / impossibility predicates and counterfactuals encoded exactly as defined • Test suite that mirrors every lemma and example (>95 % coverage, mypy-typed) • Reproductions of key results: time-keeping substrates, irreversibility proofs, quantum branching tasks, and a…
2025 · github.com · its alternatives →
- 12
I started writing this book 10 years ago in JavaScript, got through a few chapters (asymptotic notation, basic techniques, start of sorting), and then abandoned it. Recently I picked it back up, converted everything to TypeScript, and used AI (Zenflow [1] + Claude Opus 4.6) to complete the remaining chapters. I provided the structure, direction, and initial chapters; the AI generated the bulk of the remaining content under a spec-driven workflow. The book covers roughly a first 1-2 year CS curriculum: sorting, dynamic programming, graph algorithms, trees, heaps, hash tables, and more. All…
Mar 2026 · amoilanen.github.io · its alternatives →
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Hey HN, I wanted to share the new online playground for Salt (https://salt-lang.dev/playground/), a sovereign systems language designed for high-performance, distributed workloads where paying an "abstraction tax" is no longer acceptable. We started building Salt to bridge the gap between the raw power of manual pointer arithmetic and the safety guarantees of modern high-level languages. The architecture relies on an MLIR-based backbone and a Z3-powered "formal shadow," and the design is rooted in three main pillars: Fast Enough: The target is to stay within 20% of C's…
Jul 2026 · salt-lang.dev · its alternatives →
- 14
When building workflows that rely on LLMs, we commonly use structured output for programmatic use cases like converting an invoice into rows or meeting transcripts into tickets or even complex PDFs into database entries. The model may return the schema you want, but with hallucinated values like `invoice_date` being off by 2 months or the transcript array ordered wrongly. The JSON is valid, but the values are not. Structured output today is a big part of using LLMs, especially when building deterministic workflows. Current structured output benchmarks (e.g., JSONSchemaBench) only validate…
Apr 2026 · interfaze.ai · its alternatives →
- 15
A guide to functional programming
2016 · amazon.com · its alternatives →
- 16CA
2017 · billsix.github.io · its alternatives →
- 17
Full-stack CRUD, simplified, with SSOT TypeScript entities - Release v0.18.0 · remult/remult
2023 · github.com · its alternatives →
- 18
Current support for nonlinear inequalities in Lean is quite limited. This package attempts to solve this. It contains a collection of Lean4 tactics for proving polynomial inequalities via sum-of-squares (SOS) decompositions, powered by a Python backend. You can use it via Python or Lean. These tactics are significantly more powerful than `nlinarith` and `positivity` -- i.e., they can prove inequalities they cannot. In theory, they can be used to prove any of the following types of statements - prove that a polynomial is nonnegative globally - prove that a polynomial is nonnegative over a…
Apr 2026 · github.com · its alternatives →
- 19
TLDR: A small, vendor-agnostic inference loop that turns token logprobs/perplexity/entropy into an extra pass and reasoning for LLMs. - Captures logprobs/top-k during generation, computes perplexity and token-level entropy. - Triggers at most one refine when simple thresholds fire; passes a compact “uncertainty report” (uncertain tokens + top-k alts + local context) back to the model. - In our tests on technical Q&A / math / code, a small model recovered much of “reasoning” quality at ~⅓ the cost while refining ~⅓ of outputs. I kept seeing “reasoning” models behave…
2025 · github.com · its alternatives →
- 20
It all started with a conversation among friends about limitations in current multi-agent orchestration frameworks. We faced issues like limited control over agent memory and state, complicated persistence, scaling problems, and lack of type safety in Python-based tools. These challenges inspired us to try something different. The result was GraphFlow, a Rust-based lean framework for orchestrating multi-agent workflows that's simple, scalable, and robust. Its key features include: Graph-based orchestration: Easily define workflows using nodes and edges. Lean Execution Engine: A minimal and…
2025 · github.com · its alternatives →
- 21
I spent months running experiments on what language models do when they encounter inputs outside their training distribution — random phonemes, invented morphemes, Wierzbicka's semantic primitives. The finding that surprised me: Language model behavior follows a reproducible taxonomy (Synthesis, Collapse, Overflow, Metacognition, Linguistic Drift). It's not random noise — it's classifiable. The finding that matters for interpretability: Structure is a more reliable control variable than content. Telling a model how to structure reasoning produces consistent outputs. Telling it what to reason…
Mar 2026 · github.com · its alternatives →
- 22
Google Zanzibar datalog lang lets you describe concepts and express how they are related. I generalize it to DSL you can use on Lean4 (and other languages) this lets you represent a knowledge base you can construct, store and evaluate, have it under git and improve without big engines or relaying on external infrastructure. Google's Zanzibar paper: https://storage.googleapis.com/gweb-research2023-media/pubto...
Jul 2026 · github.com · its alternatives →
- 23
A Cloud monad based on transient for the creation of Web and reactive distributed applications that are fully composable, where Web browsers are first class nodes in the cloud - GitHub - transient-haskell/transient-universe: A Cloud monad based on transient for the creation of Web and reactive distr
2016 · github.com · its alternatives →
- 24
A native Rust library for Delta Lake, with bindings into Python - delta-io/delta-rs
2022 · github.com · its alternatives →
Also compare
- Formally verified 3D CSG: Trust 93 lines spec, not 1000 lines AI code alternatives
- Formalizing Principia Mathematica using Lean alternatives
- Formal Verification for Machine Learning Models Using Lean 4 alternatives
- Talos – Open-source WASM interpreter for Lean alternatives
- “Statements and State”, the next chapter of my book on interpreters alternatives
- Remult – a CRUD framework for full-stack TypeScript alternatives
Ranked by how close each launch is in meaning, then by votes. Prices were read from each product’s own site when checked and can change. Refine with your own description →