A region/patch of space-time is also a space-time.

[Audio] In physics, spacetime is a mathematical model that combines the three dimensions of space and one dimension of time into a single four-dimensional manifold. Each point in this manifold corresponds to an event in reality. Basically point p1 (x,y, z,t) will be an event happening in space co-ordinates x,y,z and time t according to a frame of reference. A region or patch in spacetime is also a spacetime because it has 3 space dimensions and 1 time dimension and a point on that region of space time corresponds to an event in the reality happening on the space and time co-ordinates defined in that region. Think of it like this:- A subset of a line-segment is also a line-segment or a subset of an arc is also an arc, a region of a surface is also a surface. In fact, Einstein's general relativity uses the same concept. It divides a curved spacetime into infinitesimal regions of flat spacetimes and uses special relativity on those flat spacetimes..

[Audio] Parallel doesn't mean equal. It just means similar in non-mathematical context. The misconception comes from parallel lines "having the same distance continuously between them at each point." But the ' distance' between two line segments is defined as the perpendicular distance. So you ' project' a line segment to find that perpendicular distance. A projection doesn't change the length of the segment. A trapezium has parallel sides but they are not equal in length..

[Audio] Following are the possibilities for otsutsuki's dimensions. First possibility of Otsutsuki's dimension :- Dimensions' reality explained by regions of space time in the same universe. The dimensions are in the same universe and the reality in those dimensions is explained by different regions of spacetime which are referred to as spacetimes themselves..

[Audio] Second possibility of Otsutsuki's dimension :- Dimensions' reality explained by different spacetime in a different universe. The dimensions can be inside different universes and hence their reality will be explained by different space times. (Does not necessarily make dimensions universal) Each universe has it's own space-time continuum and the main axes represent a higher dimensional space for the following 2D universe..

[Audio] The first possibility that the dimensions' reality is explained by regions of spacetime is more likely. Why ? As explained in part 1, Kara HQ has been stated to be in another dimension. That dimension has been stated to have the same time as Konoha village. Two completely different spacetimes which explain different universes, cannot have same time..

[Audio] Eida has been stated to see everything in the world. Eida was able to see into 2 dimensions, one where Boruto teleported Isshiki and the other when jigen stored juubi. World can at max mean universe, which means the 2 dimensions were inside the same universe..

[Audio] Isshiki says that the otsutsuki will is to go forth and devour planet after planet across space. He says "space" not " spaces". Why would he ask code to eat planets across only 1 space when code can use space-time ninjutsu ? And since it's the otsutsuki will, all otsutsuki do that..

[Audio] Kaguya connects the spacetimes when she moves between them. You connect two different regions in the same space time continuum. Connecting two different space times isn't the popular way to move between universes and no one does that. The way you move between universes is going through a black hole and you exit through a white hole and keep on repeating. A black hole and white hole are already connected. You don't need to connect anything. But you need to connect two points by warping the space from each side. Hence, it's more likely that kaguya is connecting two different regions of spacetime..