Can the complete physical structure of the universe be described by a two-brane matrix? First, we need some key words taken from the glossary of Brian Greene's book "The Elegant Universe." Brane. Any of the extended objects that arise in string theory. A one-brane is a string, a two-brane is a membrane, a three-brane has three extended dimensions, etc. More generally, a p-brane has p spatial dimensions. Closed string. A type of string that is in the shape of a loop. Open string. A type of string with two free ends. Curled-up dimension. A spatial dimension that does not have an observably large spatial extent; a spatial dimension that is crumpled, wrapped, or curled up into a tiny size, therby evading direct detection. Extended dimension. A space (and spactime) dimension that is large and directly apparent; a dimension with which we are ordinarily familiar, as opposed to a curled-up dimension. Dimension. An independent axis or direction in space or of spacetime. The familiar space around us has three dimensions (left-right, back-forth, up-down) and the familiar spacetime has four (the previous three axes plus the past-future axis). Note: Although superstring theory requires the universe to have additional spatial dimensions, it is the purpose of this thread to show otherwise.