Impossible

From APIDesign

Explaining something is impossible, is well, impossible. Or at least almost impossible as following few stories show.

You Are the Expert!

Following viral video demonstrates the principle:

You are the expert! Can you do it? And don't tell us it is impossible, as that can only be explained as your own incapability.

Finite-state Machine

This story requires you to understand what a Finite-state automaton is and how it differs in capabilities from a pushdown automaton or at least from Turing machine - e.g. classical computer. This kind of knowledge should be approachable to every expert who studied computer science, or who studied lingustics and knows who Chomsky and his hierarchy is. I heard the story when I was studying MatFyz by Michal Chytil, who at the time was not only computer scientist, but also partner of Anderson Consulting in our country and his stories about business vs. science relation were absolutely revealing.

Imagine your are an expert in the area of Finite-state automatons. Your great reputation lead another potential customer to you and you are being asked to create a new Finite-state automaton that will:

Recognize words composed from 0 and 1 alphabet letters.
Accept words that start with some number of 0 and are followed by the same number of 1.
Reject all other words.

Your new automaton should then accept word like "01" or "000000000111111111" and reject words like "10" or "00010" or "001". What should you say to such customer?

The right answer is to say: "It's impossible!" It is enough to read description of wikipedia:pushdown_automaton, but of course, your customer is clueless and won't bother. Even if you try to explain what the problem is, the customer will only believe that you are incapable. Your great reputation is being lost. Morever there is another company specialized in construction of Finite-state automatons and when your customer visits them, they (as good business men) say: "Of course, we'll build the automaton!"

TBD