Łoś–Tarski preservation theorem

The Łoś–Tarski preservation theorem is a fundamental result in model theory, a branch of mathematical logic that deals with the relationship between formal languages and their interpretations, or models. The theorem specifically addresses the preservation of properties of structures (models) under certain mappings. In more detail: 1. **Setting**: The theorem considers a first-order logic and a class of structures (models) defined by certain properties.