Is the relationship between subtype polymorphism and the Liskov principle the same concept or do they have different ideas?

The relationship between subtype polymorphism and the Liskov principle exists, but they are not the same. Subtype polymorphism is the ability to use objects of subclasses where an object of the superclass is expected, meaning objects of different types can be processed uniformly.

The Liskov Substitution Principle (LSP) is a rule that states that objects of a subclass should be interchangeable with objects of the superclass without violating the correctness of the program. In other words, a subclass should preserve the behavior expected from the superclass.

In other words, subtype polymorphism is a mechanism, and the Liskov principle is a constraint that guarantees the correct use of this mechanism. Without adhering to LSP, polymorphism can lead to errors and unpredictable behavior.