<person> (1878-1929) A Danish mathematician. Erlang the
language and unit were named after him.

Interested in the theory of probability, in 1908 Erlang
joined the Copenhagen Telephone Company where he studied the
problem of waiting times for telephone calls.

He worked out how to calculate the fraction of callers
who must wait due to all the lines of an exchange being in
use. His formula for loss and waiting time was published in
1917. It is now known as the "Erlang formula" and is still
in use today.