Yes, they display the same information, both 2048x1536 pixels showing the exact same amount of information. So, for instance, the status bar at top, the clock will appear a bit smaller on the mini. You have the same number of app icons on screen. (No extra rows on full-size iPad). This is not the same thing as going from 3.5 to 4" iPhone screens, that's entirely different.
the iPad Mini retina has the same screen resolution (326PPI) as the retina iPhones, so it will look as sharp as the iPhones.
the retina iPads are not quite as sharp (264PPI), they have slightly bigger pixels since they have the same amount of pixels as the retina mini.
So, on one hand, the mini retina's screen, you won't be able to see the pixels. But, on the other hand, (either mini), is a reduced version of the full sized iPad screen, so, some things are shrunk down.