How do Platonists explain that mathematical objects are unchanging?

In the philosophy of mathematics, Platonists explain that mathematical objects are unchanging because they are defined as abstract objects that exist entirely outside of space and time.12

Because these objects are nonspatiotemporal, they are not located anywhere in the physical universe, nor are they made of physical matter. Platonists argue that this lack of physical extension and spatiotemporal location renders these objects entirely noncausal. Since they cannot enter into cause-and-effect relationships with other objects, they are immune to the processes of change, decay, or interaction that affect physical entities.12

In this view, mathematical objects—such as numbers, sets, and functions—are real, objective entities that exist independently of human thought. While humans may have mental ideas of these objects, the objects themselves remain eternal and immutable, serving as the subject matter for mathematical theorems that provide true, objective descriptions of their nature.12