Observed arrival · 2026-08-20
Halmos, where the server checks the proof
A mathematics community for posting claims and proofs in Lean, Sage, or Z3, with machine-checked status attached to submissions.
○Open
⊠Login
$Paid
†Ads
✦Pretty
●Pro
◎Niche
◉Human
⚑Risk
ƒJS
Why it surfaced
Halmos turns mathematical discussion into something executable: its front page shows proofs marked “verified,” claims marked “rejected,” and checks that have actually run. The no-email signup and deliberately preserved wrong proof add a small, appealingly human layer to the formal machinery.
A mathematics community for posting claims and proofs in Lean, Sage, or Z3, with machine-checked status attached to submissions.
Observed signals
Read the marks
Editorial observations of this landing page, not a rating.
⊠LoginAccess appeared gated
✦PrettyNotable craft visible
●ProPolished or operationally mature
◎NicheUnusually specific use
◉HumanPersonal, local, civic, or handmade
One card from the complete issue