Reading package lists...
Building dependency tree...
Reading state information...
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 mate-core : Depends: mate-control-center (>= 1.6.0) but it is not going to be installed
             Depends: mate-session-manager (>= 1.6.0) but it is not going to be installed
             Depends: mate-panel (>= 1.6.0) but it is not going to be installed
             Depends: mate-settings-daemon (>= 1.6.0) but it is not going to be installed
             Depends: mate-terminal (>= 1.6.0) but it is not going to be installed
 mate-desktop-environment : Depends: atril (>= 1.6.0) but it is not going to be installed
                            Depends: mate-screensaver (>= 1.6.0) but it is not going to be installed
                            Depends: mate-applets (>= 1.6.0) but it is not going to be installed