It looks like the word "and" was used incorrectly here. It makes more sense if you pull the word out. "Corresponding gaps" just means it showing you the gaps on the last column. That's how I would interpret it.

I found the original and couldn't understand it. It's the title of a graph. It looks like "base-case" means the minimum acceptable case. He may have meant "gaps in..." which possibly means missing information. "corresponding" is used wrongly. I think the whole document was proofread and corrected well but this title was missed.