  We have observed the Class 0/I protostellar system Ced110 IRS4 at an angular
resolution of $0.05''$ ($\sim$10 au) as a part of the ALMA large program; Early
Planet Formation in the Embedded Disks (eDisk). The 1.3 mm dust continuum
emission reveals that Ced110 IRS4 is a binary system with a projected
separation of $\sim$250 au. The continuum emissions associated with the main
source and its companion, named Ced110 IRS4A and IRS4B respectively, exhibit
disk-like shapes and likely arise from dust disks around the protostars. The
continuum emission of Ced110 IRS4A has a radius of $\sim$91.7 au
($\sim0.485''$), and shows bumps along its major axis with an asymmetry. The
bumps can be interpreted as an shallow, ring-like structure at a radius of
$\sim$40 au ($\sim0.2''$) in the continuum emission, as demonstrated from
two-dimensional intensity distribution models. A rotation curve analysis on the
C$^{18}$O and $^{13}$CO $J=2$-1 lines reveals the presence of a Keplerian disk
within a radius of 120 au around Ced110 IRS4A, which supports the
interpretation that the dust continuum emission arises from a disk. The
ring-like structure in the dust continuum emission might indicate a possible,
annular substructure in the surface density of the embedded disk, although the
possibility that it is an apparent structure due to the optically thick
continuum emission cannot be ruled out.
