What's the difference between abstraction and generalization?

Question

I understand that abstraction is about taking something more concrete and making it more abstract. That something may be either a data structure or a procedure. For example:

Answer 1

Abstraction is usually about reducing complexity by eliminating unnecessary details. For example, an abstract class in OOP is a parent class that contains common features of its children but does not specify the exact functionality.

Generalization does not necessarily require to avoid details but rather to have some mechanism to allow for applying the same function to different argument. For instance, polymorphic types in functional programming languages allow you not to bother about the arguments, rather focus on the operation of the function. Similarly, in java you can have generic type which is an "umbrella" to all types while the function is the same.