Date: Jan 25, 2013 4:47 AM Author: William Elliot Subject: Re: What is a projection of an n-tuple? On Thu, 24 Jan 2013, Peter Percival wrote:

> Writing <...> for an ordered n-tuple; is the second projection of

> <x,y,z> y or <y>?

pi_2(<x,y,z>) = y

pi_2({<x,y,z>}) = {y}