  We begin from the quantization algebras and constraint for analyzing the
choice of centers in the first-order formulation without losing generality.
Then we calculate the entanglement entropy in the non-interacting $p$-form
theory in $2p+2$ dimensional Euclidean flat background with an $S^{2p}$
entangling surface. The universal term of the entanglement entropy in the
non-interacting $p$-form theory is determined in terms of the universal terms
of the non-interacting zero-form theory. We also prove the strong subadditivity
in the non-interacting theory with the non-trivial centers. Finally, we
calculate the mutual information with centers in two-dimensional conformal
field theory. The result shows that the mutual information is independent of
the choice of centers.
