Proof checking

Tactic

A procedure that constructs or refines a proof.

Definition

Tactic

A tactic reads a proof state and tries to produce proof terms or smaller goals.

Tactics automate common reasoning patterns and search. In a kernel-based system, their output must still pass the kernel.

01

Example

An induction tactic can create a base goal and an inductive-step goal for a statement about natural numbers.

02

Important distinction

A tactic succeeding does not bypass the kernel unless the system explicitly trusts that tactic as an axiom or oracle.

After reading this article, you should be able to

  • Define Tactic in the sense used on this site.
  • Describe how tactic execution relates to the proof term checked by a kernel.