Project-declaredLean 4.32.1
Replacement rel exists Unique of mem exists Unique
LO.FirstOrder.SetTheory.replacement_rel_existsUnique_of_mem_existsUnique
Project documentation
A stronger variant of (unique existence of) replacement, which only requires uniqueness on X. The statement of this lemma is thanks to tosiaki.
formal logicmetatheoryproof theory
Source project: Foundation
Person-level attribution pending.