Infinity is the non-existence of a limit, and if a non-existence existed it wouldn't be a non-existence. There is obviously a finite distance between every two points in the Universe, but there is no point, however distant, where the Universe ends. Some mistakenly believe that if there is a finite distance between every pair of points then the farthest point in the cosmos must be a finite distance away. What they don't understand is that just defining two points sways the realm of their consideration from the infinite back to the finite. When dealing with infinity, there is no limit, there is no 'farthest' and there is no 'all'. The fact that no defined point of infinity exists serves only to further validate the concept.

Only three independent values (XYZ coordinates) are necessary to uniquely specify any point of existence within the Universe - so there are said to be three 'dimensions' (more accurately, three axes). If the Universe were finite, then at any given instant and for any given point there must exist another point within a finite distance at which travel in any direction will not increase the distance between the two.

The old 'balloon ploy' is often put forth as a three-dimensional example of cosmic expansion in a four-dimensional hyperverse. So long as the balloon is expanding faster than anything can traverse it, a subject can travel forever without hitting a boundary. Stroking the ego of the unwary layman for his ability to understand a hypothetical abstraction, pundits propose this as an example of a Universe that is finite but unbounded. But it doesn't hold water. At any given instant there DOES exist a point on the balloon at which motion in any given direction will not increase the distance between the two. It is a limit, the boundary of the ability to increase distance exists.

If someone wants me to believe the universe is finite, then all they have to do is simply convince me that for some given instant the value of at least one of the XYZ coordinates has or had a limit. And if anyone wishes me to believe there are more than three dimensions, then show that there are locations in the cosmos which cannot be specified within those coordinates.

Saying infinity expands is trying to apply a relative term (infinity expands relative to WHAT?) to a non relative situation. To expand is to increase the value of some limit and only that which has a LIMIT can expand. And we (see above) have already defined Universe as everything that exists (not just the KNOWN universe).

The very definition of the terms that foolishly try to explain a 'finite but unbounded' universe are self-contradictory. Finite explicitly means a limit and either that limit exists or it does not. There is no limit that is somehow unlimited due to some esoteric process. If a limit exists, you can point to it because it must have a specific location relative to you.