A quiet little man was brought before a judge. The judge looked down at the man and then at the charges and then down at the little man in amazement.

"Can you tell me in your own words what happened?" he asked the little man.

"I'm a mathematician dealing in the nature of proof," said the little man.

"Yes, go on," said the astounded judge.

"Well. I was at the library and I found the books I wanted and went to take them out. They told me my library card had expired and I had to get a new one. I went to the registration office and got in another line. I filled out my forms for another card. I got back in line for my card."

"And?" said the judge.

"And the clerk asked me, 'Can you prove you're from New York City?'"

"What happened next?" the judge asked.

"I punched him."