Cajal

Cajal

Scaling formal verification to accelerate scientific discovery

Winter 2026ActiveB2BB2BBig DataAISan Francisco, CA, USA
Cajal (YC W26) is massively scaling formal verification to accelerate scientific discovery. We deploy superhuman AI mathematicians to high-impact applied domains, starting with quantum computing and finance. We do this with Lean - a framework that allows us to formally verify any mathematical statement, grounding AI in truth and validating the tools discovered by our systems.

Verdict

Medium Signal
Market Opportunity
Formal verification for quantum computing and finance is a real and potentially large B2B market, but the ICP is extremely narrow today and enterprise sales cycles in both verticals are long. The 'scientific discovery' framing is broad but the stated starting verticals (quantum + finance) are credible high-value domains willing to pay for correctness guarantees. TAM is real but likely sub-$1B for formal verification tooling specifically.
Medium Signal
Founder Signal
Luke Johnston has an MPhil from Cambridge in ML/Computational Neuroscience (First Class) and a UCL research internship at the Gatsby Unit — solid academic ML background but limited industry shipping experience; most recent roles are research intern and part-time Google course instructor. Pedro Nobre co-founded Vertebra (AI consulting, 2022-2024) and has some consulting/engineering background, but no deep formal verification or Lean expertise is evident. Both came through Entrepreneurs First before YC W26, suggesting the idea is relatively nascent.
Medium Signal
Competition
No competitor data was returned, but the space includes established players like Galois, Certora (smart contract verification), and academic Lean/Coq tooling ecosystems. Microsoft Research has deep Lean investments. The AI-augmented formal verification angle (e.g., Google DeepMind's AlphaProof) is increasingly crowded with well-resourced players. Differentiation claim is plausible but unproven.
Medium Signal
Product
Website is functional with full navigation (Our Work, Services, Blog, Careers, Book a Demo). Product described: Tau, a multi-agent system for discovering and verifying mathematical proofs. Six application areas (Quantum Computing, Finance, Cryptography, Aerospace, Robotics, Biology). Embedded video content. Cambridge and YC backing. No pricing, no named customers, no live demo.
OverallB Tier

Cajal is tackling a technically interesting problem in scaling formal verification with AI. The website is functional with a full product description of Tau (multi-agent mathematical proof system), six application areas, embedded video, and Cambridge backing. All signals at medium with no lows. The formal verification market is niche but high-value. Main risk is the historically slow pace of research-to-product transitions in theorem proving. Balanced signals across all dimensions.

Active Founders

Luke Johnston
Luke Johnston
Founder

Working on formal verification and AI. Background in machine learning and neuroscience at research labs in oxford/cambridge/ucl. Learn more at https://caj.al/ and feel free to get in touch at luke@caj.al

Pedro Nobre
Pedro Nobre
Founder

Working on formal verification and AI.

Cajal
Cajal
TierB Tier
BatchWinter 2026
Team Size2
StatusActive
LocationSan Francisco, CA, USA
Last Updated2 days ago