ELI5: Explain Like I'm 5

Topological degeneracy

Imagine you have a toy castle with a secret door that can only be opened if you place the right shape of key in a hidden hole. Now imagine that there are two keys - a square key and a triangle key - that both fit the hole perfectly.

In topology, we study shapes and spaces by looking at how they can be stretched or twisted without changing their basic structure. This means that even though the square and triangle keys may look different, in topology they are the same because they can both open the secret door.

This idea of having multiple ways to unlock something is called topological degeneracy. It occurs when two or more different configurations or arrangements of objects or shapes have the same topological properties.

In simple terms, topological degeneracy means that even though things may appear different or have different characteristics, they can still be considered "the same" because they have the same topological features. It's like having different keys that can open the same lock - they may look different, but they can all do the same job.