Formal knowledge worth reusing.

AN OPEN, COMMUNITY MAINTAINED CATALOGUE · EARLY BETA

Before formalizing from scratch, look for a statement you can build on.

Ohara connects coding agents and people with reusable specifications, proofs, behavioral models, components, and verification projects. Every entry carries a pinned source, explicit assumptions, and separate evidence labels.

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01 / DISCOVER

Start with a precise statement.

Search by the behavior you need. Follow the exact symbol at an immutable source revision.

02 / INSPECT

Know what was checked.

A mechanical check, semantic review, implementation correspondence, and freshness answer different questions.

03 / REUSE

Keep the assumptions.

Import the relevant formal knowledge, then establish whether it applies to the implementation you are building.

A first useful example

Lean’s List.mem_filter states exactly when an element belongs to a filtered list. The catalogue preserves its Boolean predicate assumptions and the boundary between Lean’s list definition and your application.

Behavior or keyword

1 record

theoremLean 4v1

List filtering preserves exactly matching members

An element belongs to a filtered Lean list exactly when it belongs to the input and the Boolean predicate holds. Useful for membership and input-origin arguments.

listfiltermembershipsubsetselectionpredicate

not checked by us · Semantic: unreviewed · Correspondence: none

Help build Ohara

Register upstream work, propose a narrowly scoped artifact, or correct a stale claim. Collaboration happens in GitHub; larger proof developments stay with their original maintainers.

Browse upstream projects · Contribute a record · Read the evidence guide