Ahh, audiophiles

I've always enjoyed audiophiles; it's pretty hard to find a single group with so much rich potential for mockery. But, through all my laughter at their talk of high quality digital cables (they haven't heard of error correction perhaps?); through all the sniggering over their detailed discussions about bit rates when the Nyquist-Shannon sampling theorem is a mystery unto them (What? Perhaps the CD sound frequency of 44.1kHz being approximately twice the typical highest human-audible frequency is a coincidence?)

Anyway, for all that I've always just thought it was funny: Ahh, aren't they cute? No knowledge of information theory at all, but here they are arguing about transmitting bits. Still cute though. Just a geeky hobby, kind of like theology. Theologians and audiophiles arguing about things that aren't really going to have any effect on their lives, that they don't understand, and in the end are all indistinguishable.

And I've always assumed that on some level audiophiles knew just how ridiculous they were. They'd never admit it, but there was always something in there that would prevent them from doing something really stupid. But, no!

Behold! The $500 Ethernet Cat-5 cable! And it's not even blue, like a proper one! And they're available used! Some idiot actually bought one of these!

Oh, and please, please, please can an audiophile attempt to defend this? I won't respond, but it's always amusing to listen to.

What is this Property?

I'm not a mathematician, just a computer scientist with an interest in maths, so please excuse the simplifications and inaccurarcies in this. I'm going to describe this with some rigour, but I'm bound to get things slightly wrong, please bear with me.

In maths, a function is defined as a relation between the members of two sets, S and R, that produces members of the third set T. Looking at it another way, the set T is defined by the function. Some functions, taking two arguments from the same set S, always produce members of that set S. Addition across the natural numbers is an example of that: for any two numbers greater than 0, the sum will always be a number greater than 0. There are many functions that behave like this.

Functions have properties. A property describes a rule that a function obeys for given sets of parameters. From a mathematics perspective, these properties are interesting. For example, addition across the natural numbers is associative. This means that no matter what order the parameters to the addition function are arranged, the answer will be the same: 2 + 3 = 3 + 2. Fairly simple and obvious, right? But from the same property we can also say 2 + (5 + (6 + 11)) = (2 + (5 + 6) + 11). This is interesting because once we know that a function has the associative property we can arrange the parameters of the function without changing the meaning: this is useful in proofs.

There are many, many of these properties, and most of the interesting ones have names: associative, commutative, distributive. For the last year I've been trying to find out if another property I've noticed also has a name.

Take the function minimum across the natural numbers. Given the sets {4, 6, 100, 1, 43} and {1} minimum gives the same answer: 1. The result of the function minimum is determined by only a single member of the set, no matter how large the set.

Take the function and across the booleans. Given the set {true, true, true, false, true} the answer is false. It doesn't matter how many true's are in the set, the answer will always be false.

And I'm sure you can imagine other functions that behave like this. My question is: does this property have a name, and if it does, what?

If I was more of a mathematician, I'm sure I could actually describe this property a lot more accurately. In fact, I'm not entirely sure there is a consistent property here, and I have no idea if it's interesting if it does exist. But I notice this often, and it sure feels like it should have a name.

Functions whose result is determined by a single member of the parameter set, irrespective of the size of that set: do these have a common property?