[Math] size of an independent set of any graph with $n$ vertices and maximum degree $d$

graph theory

I have to show that any graph with $n$ vertices and maximum degreee $d$ contains an independent set of size at least $\frac{n}{d+1}$. Why $d+1$? Can you please help me or give me a hint? Thanks a lot!

Best Answer

Take a vertex $v$ with $d$ neighbors. That's $d+1$ vertices.

Add $v$ to your independent set.

Remove $v$ and its neighbors from $G$ and repeat.

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