In entanglement studies, it is convenient to write the reduced density matrix of a subsystem in the form exp(-H), where H is called the entanglement Hamiltonian. This operator has a particular form in real space which is related to the way the total system is partitioned.
In the talk, H will be discussed for a large interval in an infinite discrete chain of free fermions in its ground state. Very accurate numerical calculations are presented, and it is shown how one can obtain H analytically with the help of a commuting operator using asymptotic results found previously in a different context. Differences to the conformal expressions remain and are attributed to the discrete nature of the problem. Some related topics are mentioned.