Eddie and Erdős

Today I read Eddie a picture book about Paul Erdős, The Boy Who Loved Math. (At one point he demanded "Did I pick this book?" and I had to admit that no, Papa picked this book.)

Near the end it mentions Erdős numbers and has a graph with pictures of people and their connections, with numbers one and two. Eddie said "I wish I had Erdős number one."

"Well, that's impossible now," I said, "because—"

"I mean, I wish I had Erdős number three!" he said.

"OK!" I said. "We can do that. If you write a paper with me someday, you'll have Erdős number three."

"Yeah!" he said. "We'll write a paper together."

After we finished the book, he was ready to start right away. "Let's write a paper, Papa."

So, we did.

So Eddie's Erdős number is 3.