The proof stamp
Every claim,
checked in the open.
Paste a claim or an AI answer. A machine works out the math in it and checks it against the facts in the Atlas. Each claim comes back Proven, False or Not checked, with a receipt anyone can rerun.
Today it checks sums, percents, units, primes and the Atlas facts. History, health and news say Not checked, which never means false. You pay only for a signed stamp.
The box above replays real facts from the Atlas, each one accepted by the Lean proof checker. See every fact or every attempt.
How it works
Three steps, every time.
Paste it
Any answer, post or homework. It is split into sentences, and the math inside each one is found.
The machine checks
The math is worked out exactly, with fractions, units and primes, or matched word for word to a fact a proof checker accepted.
You get the receipt
Each claim gets its label and a receipt anyone can rerun. Nothing is hidden.
The four labels
How sure we are, in one word.
Every fact in the Atlas carries one of these. A check you run here answers Proven, False or Not checked.
Checked by a computer proof. It holds, every time.
Matched to a real measurement and its source.
A careful argument, each link shown. Not a proof.
Nothing backs it yet. We say so out loud.
The library
Facts the machine has proven.
Plans
Pay only for the stamp.
One Stamp
- One file checked
- Signed only if it passes with no gaps
- A timestamp anyone can check
Checker
- 100 checks a month
- Every check stamped, full receipt
- Cancel any time with one email
Proven Standing
- Your public claims kept checked
- A public page of what holds
- We tell you first when one breaks
Questions
What people ask first.
Who does the checking?
A machine. The math in what you paste is worked out exactly, and every Atlas fact was accepted by a proof checker (Lean 4). People write the rules, not the verdicts. Matching numbers to their sources and tracing arguments are being built; until then those claims say Not checked.
What if you are wrong?
Every receipt can be rerun by anyone. If a label breaks, the receipt shows where, and the label changes in public.
Why not just say true or false?
Because most claims are not proven either way. The label says how sure anyone can honestly be.
Is my text kept?
No. The check runs in your own browser, so what you paste is not sent anywhere. A stamp you pay for keeps a fingerprint of the file, not the file.