[Math] Incidences of rigorous proofs used in legal proceedings

reference-requestsoft-question

Motivation: Loius Pojman mentions in What Can We Know? (2001) of a certain Carneades (ca. 214-129 B.C>) who must have been a "remarkable dialectician"because " in 155BC he was sent on a diplomatic mission to Rome and in his spare time he gave two lectures. On first day he eulogized justice, making a profound impression on his audience. To their amazement on the second day he gave a diatribe against justice, arguing that there were equally good reasons for not adopting it".

Research yielded the Carneades argumentation framework.
However I am interested in the more recent ones. Here's one:

The Mathematical Proof that got a Physicist out of a Traffic Ticket

Dmitri Krioukov, a UC San Diego
physicist, was recently given a ticket
for running a stop sign. He went to
court to argue the ticket, armed with
a scientific paper that mathematically
demonstrated that he really had
stopped. He won.

Krioukov has since posted the entire
paper, rather immodestly called "The
Proof of Innocence", on the arXiv
server. It's probably debatable how
much his ironclad mathematical
reasoning really helped determine his
innocence – it's just as likely the
judge threw out the ticket when it was
demonstrated another car had
obstructed the ticketing police
officer's view. Still, let's take a
look at…

Full ezine article

Here is the arXiv paper.

Are there any similar cases?

EDIT: Peter Suber has a description of the case on the famous Paradox of Court here.

Best Answer

This is perhaps a borderline example. I heard this story from BCnrd a few years ago, so I hope it hasn't been too mangled in my head since then.

One day, Ken Ribet got a phone call in his office:

  • "Is this Professor Ribet?"
  • "Yeah."
  • "Could you tell me what one tenth of one percent means?"
  • "One part in a thousand."
  • "Are you willing to give that answer under oath?"

It turns out that someone around Berkeley had rented some property, and the rental contract specified that the landlord could not increase the rent by more than one tenth of one percent each year. When the landlord tried to raise it by more, the tenant sued.

At the trial, the tenant's lawyer called in the expert witness. They swore him in, asked him about his job and his qualifications, then came the key question:

  • "Professor Ribet, what, in your expert view, is one tenth of one percent?"
  • "It's one part in a thousand."

Before he could give a rigorous proof, the landlord's lawyer said, "Objection! Anyone reading the contract can tell that it obviously meant one part in 10." The judge agreed, and threw out the case.

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