Proof of `Types are determined by types in a neighborhood`
groundedproofs/Lax185574Proofs/LocalToGlobal.lean · lax-185574
What this proof establishes
Assuming the claims on the left, the claim on the right holds — checked by the archive's pipeline. Proof code is not displayed here.
In the paper
- page 63 of this submission's paper
Description
Let be given by . A formula of rank at most uses finitely many relation symbols. Over the sublanguage of these symbols it is equivalent, on finite structures, to a Boolean combination of basic -local sentences and -local formulas of rank at most . The sentences have the same truth value for both tuples. A local formula holds of a tuple in the structure if and only if it holds in the induced substructure, by , since the balls of the sublanguage are contained in those of . In the induced substructures, the two tuples satisfy the same formulas of rank at most .