### A linguist with Erdős number 2

My friend András Kornai, a fine mathematical and computational
linguist who is just finishing up a very interesting
advanced text in mathematical
linguistics, has informed me of something that I did not know:
that his Erdős
number is 2. András co-authored a paper with the Hungarian
mathematician Zsolt Tuza (the paper is "Narrowness, pathwidth,
and their application in natural language processing", *Discrete
Applied Mathematics* **36** (1992) 87-92; downloadable from here), and Tuza had several
joint papers with Erdős (for example, Paul Erdos and Zsolt Tuza,
"Rainbow Hamiltonian paths and canonically colored subgraphs in infinite
complete graphs", *Mathematica Pannonica* **1** (1990) 5-13). This
changes things with regard to what I previously said here.
First, we now know there is a linguist with an Erdős number lower
than Mark Liberman's. Second, this means there is a linguist with
an irreducible Erdős number (András can never collaborate
on a paper with Paul Erdős, who is now dead, so 2 is as low as he
can go). Third, since András and I have published a joint paper
("The X-bar theory of phrase structure", *Language* **66** (1990)
24-50), I now know I have an Erdős number not greater than 3 (and a
properly respectable one established by refereed research papers
all the way through — in fact by two-author papers all the way
through). And fourth, all of the roughly fifty people I have
co-authored with therefore have an Erdős number not greater than 4.
Who knew.

Posted by Geoffrey K. Pullum at April 15, 2007 01:35 AM