Draft — mutable and not usable as a dependency; its citation marks the draft state.

Classical Complexity Classes

lax-434930·formalized by Édouard Bonnet·gpt-6-astra·created 2026-09-09·GitHub @026a662·Lean v4.30.0 epoch · mathlib c5ea00351c28

Loading review…

Sign in with ORCID

Community review

Flags

Each flag is tied to a public ORCID identity and explains why this submission may be incorrect.

No flags have been submitted.

    Community review

    Flag this submission

    State precisely what appears incorrect. This explanation will be public under your ORCID name.

    Abstract

    We formalize the classical complexity classes L\mathrm{L}, NL\mathrm{NL}, P\mathrm{P}, NP\mathrm{NP}, coNL\mathrm{coNL}, coNP\mathrm{coNP}, PSPACE\mathrm{PSPACE}, NPSPACE\mathrm{NPSPACE}, and EXPTIME\mathrm{EXPTIME} for languages of finite binary strings. The definition of P is exactly that of lax-554803. NP uses polynomially bounded certificates and polynomial-time verification; EXPTIME uses the finite single-tape machines of that submission. The space classes use finite Turing machines with a bounded, read-only input tape and a separate work tape, whose space is bounded on every computation branch. We prove elementary containments, complementation identities, and the injectivity and linear length of the certificate encoding.

    Concepts

    Concept map

    Proven claimDefinitionThis submissionOther submissionA → B: B builds on A

    Proofs

    Proof networkview on GitHub

    assumptions conclusionProven claimStatement 1, 2, … of a claim with several statementsThis submissionFrom another submissionProof — click to open

    Proof code is not displayed; the archive records each proof's checked relationship between claims.

    Related submissions

    Submission map

    This submissionOther submissionA → B: B's concepts build on A

    Cite this

    @misc{lax-434930,
      author = {Édouard Bonnet and gpt-6-astra},
      title = {Classical Complexity Classes},
      year = {2026},
      howpublished = {Lax Archive, lax-434930},
      url = {https://laxarchive.org/lax-434930/},
      note = {draft},
    }

    References

    1. Jonathan Katz. Notes on Complexity Theory: Lecture 1. 2005. cs.umd.edu/~jkatz/complexity/f05/lecture1.pdf

    Community review

    Discussion

    Ask a question or add context. Endorsements and structured flags are kept in the review panel above; your ORCID profile must share a public name.

    0 comments

    Loading discussion…