Graphic Sequence
1. **State the problem:** Determine if the sequence $5, 4, 3, 2, 1, 0$ is graphic, meaning it can represent the degree sequence of a simple graph.
2. **Recall the definition:** A sequence is graphic if there exists a simple graph whose vertex degrees correspond exactly to the sequence.
3. **Apply the Havel-Hakimi algorithm:**
- Start with the sequence sorted in non-increasing order: $5, 4, 3, 2, 1, 0$
- Remove the first degree $d=5$ and subtract 1 from the next $d=5$ degrees.
4. **Check feasibility:** The sequence has 6 terms, so the maximum degree is 5, which is valid since a vertex can connect to at most 5 others.
5. **Subtract 1 from the next 5 degrees:**
- The next 5 degrees are $4, 3, 2, 1, 0$
- Subtracting 1 gives $3, 2, 1, 0, -1$
6. **Check for negative degrees:** The last term is $-1$, which is invalid.
7. **Conclusion:** Since the sequence after subtraction contains a negative number, the original sequence is **not graphic**.
**Final answer:** The sequence $5, 4, 3, 2, 1, 0$ is not graphic, so no graph can be drawn with this degree sequence.