I find some things to be a bit difficult to understand in math. As such, I will put some “jargon” here. This is definitely not jargon, but a notation on how things are written.
- In Norms and Spaces we defined a metric on a set as a function but what does that even mean? is the Cartesian product, or the set of all ordered pairs where x and y both come from S. Ex. if then . Furthermore, means that is a function whose input is one such pair and whose output is a real number. So is a single real number for each pair.
- The notation is used when we are defining something new, while implies regular equality.