How to call PHP a class from parent namespace?

I have the following namespace structure with the following class files

Application
|->App.php
|->Top
   |->Start.php
   |->Process.php
   |->Child
      |->Plugin.php

So in App.php I've declared

namespace Application;

in Startp.php declared

namespace Application\Top;

in Plugin.php declared

namespace Application\Top\Child;

I see that I can call the Plugin.php class from the App.php like

$object = new Top\Child\Plugin();

if it's a child/grandchild namespace, but what if I want to call Process.php from Plugin.php, which is the parent namespace from the branch? Is there something like double dots ".." to indicate the upper parent directory in namespace? I am trying to call something like

File: Plugin.php

$object = new ..\Process();

it didn't work, it looks like I can only start all the way from the root like

$object = new \Application\Top\Process()

Is this the only option? Thank you!