# Is the system of measuring length in the US Turing complete?

Little known fact, the system of measuring length in the US is Turing complete

My question is: Is the system of measuring length in the US Turing complete?

• I think the author means it as a joke. The measurement system, while certainly intricate and needlessly complex, doesn't look like the right kind of object to be Turing-Complete. It's just a weighted complete graph of conversion factors where the weight on $u\overset{w}{\rightarrow}v$ is the conversion factor from $u$ to $v$. As a stronger argument, this system preserves the parity of the input, in a sense: if $u\overset{a}{\rightarrow}v\overset{b}{\rightarrow}w$ then $u\overset{a\cdot b}{\rightarrow}w$ and $w\overset{\frac{1}{ab}}{\rightarrow}u$. Sorry to disappoint. – Lieuwe Vinkhuijzen May 19 '16 at 12:32
• We do not have a senes of humor here. – Andrej Bauer May 19 '16 at 12:59
• @AndrejBauer Perhaps we should have a new tag? – Hendrik Jan May 19 '16 at 14:01
• What would it be, joke? In that case I propose we also introduce kitten-photo. – Andrej Bauer May 19 '16 at 14:12
• @AndrejBauer Those would be tag synonyms for the real tags joke-recognition and furry-calculus-visualization respectively. Some more: for programming-related jokes I propose one-liner. For compiler fun questions -- jest-in-time along with jit as a type synonym. For computer architecture topics -- e-quip-ment. And, of course, we should get new badges: Joker(silver) and Wildcard(gold) -- *nix-pun intended. P.S. This question made my day! :) It's a pity it lacks some $\LaTeX$. – Anton Trunov May 19 '16 at 16:48