The E Theorem Prover


E is a theorem prover for full first-order logic with equality. It accepts a problem specification, typically consisting of a number of first-order clauses or formulas, and a conjecture, again either in clausal or full first-order form. The system will then try to find a formal proof for the conjecture, assuming the axioms.

If a proof is found, the system can provide a detailed list of proof steps that can be individually verified. If the conjecture is existential (i.e. it’s of the form “there exists an X with property P”), the latest versions can also provide possible answers (values for X).

Development of E started as part of the E-SETHEO project at TUM. The first public release was in in 1998, and the system has been continuously improved ever since. I believe that E now is one of the most powerful and friendly reasoning systems for first-order logic. The prover has successfully participated in many competitions.


E 2.0 Turzum is available. It features a number of improvements, including:

  1. Support for the TPTP TFF  (typed first-order form)

  2. Improved automatic and strategy scheduling modes

  3. More robust clausification performance

  4. Various minor improvements and bug-fixes

The new version is available from the Download page.

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