Limit Points Even Integers
1. **Problem statement:** We are given the set $\mathbb{Z}$ of integers with the finite closed topology and the set $E$ consisting of all even integers. We need to find the limit points of $E$ in this topology.
2. **Recall definitions:**
- A topology is called finite closed if every finite set is closed.
- A limit point $x$ of a set $A$ is a point such that every open neighborhood of $x$ contains at least one point of $A$ different from $x$ itself.
3. **Properties of finite closed topology on $\mathbb{Z}$:**
- Since finite sets are closed, their complements are open.
- Singletons $\{x\}$ are finite and thus closed.
- Therefore, every point is isolated because $\{x\}$ is closed, so $\mathbb{Z}$ is a discrete space.
4. **Implication for limit points:**
- In a discrete space, no point is a limit point of any set because we can take the singleton $\{x\}$ as an open neighborhood containing only $x$ and no other points.
5. **Conclusion:**
- The set $E$ of even integers has **no limit points** in the finite closed topology on $\mathbb{Z}$.
**Final answer:** The set of limit points of $E$ is the empty set $\varnothing$.