Run MATE on Centos/SL 7, I'd suggest opting for the "minimal" package option during initial installation (or at least not selecting an alternative desktop environment).

1. Install the epel repository:

   [root@localhost ~]# yum install epel-release

2. Install the X Window System:

   [root@localhost ~]# yum groupinstall "X Window system"

3. Install the MATE desktop:

   [root@localhost ~]# yum groupinstall "MATE Desktop"

4. Change systemd default.target to graphical.target:

   [root@localhost ~]# ln -sf /lib/systemd/system/graphical.target /etc/systemd/system/default.target

5. Switch to your new desktop environment:

   [root@localhost ~]# systemctl isolate graphical.target

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