The first and third values before a late minimum
Abstract
In a simple permutation in C whose minimum has zero-based position at least three, the first entry is exactly one more than the third entry.
Theorem 1.1 (The first and third values before a late minimum).
Lean statement: D5/S3/Combinatorics/PopStack/PopStackThirdEntry.third_entry_before_minimum
Proof. Machine-checked in Lean as D5/S3/Combinatorics/PopStack/PopStackThirdEntry.third_entry_before_minimum (✓ std3). ∎
Source. Repository-derived.
Acknowledgement. Lapo Cioni, Luca Ferrari, Rebecca Smith (2025). Sorting permutations using a pop stack with a bypass. DOI: 10.1016/j.disc.2025.114964. URL: https://arxiv.org/abs/2503.08285v1.
Commentary.
In a simple permutation in C whose minimum has zero-based position at least three, the first entry is exactly one more than the third entry.
References
- Truth anchor:
D5/S3/Combinatorics/PopStack/PopStackThirdEntry.third_entry_before_minimum - Dependency: D5/S3/Combinatorics/PopStack/PopStackDefs