Strictly speaking neither tensile strength nor compressive strength in excessive amounts would be necessary for the structure to exist in a meta-stable state.
You could have such a ring made entirely of liquid, and it would be stable until something made a splash or a wave, and started the whole chaotic cascade that would end up, in following decades and centuries, in the whole thing coalescing into separate bodies ranging from planet-sized to black hole, many of them on collision courses with many of the others, and more than a few about to be ejected in random directions from the site.
You need active management of some kind to stop that from happening; a network of maglev tracks running around the thing might keep masses actively moving to maintain balance, concentrate mass where needed for gravitational adjustments, and, via momentum, lend some local rigidity to the structure. This is one of those things that requires minimal energy if done to absolute perfection, but would be extraordinarily hard to do to absolute perfection.
With some magmatter supporting the track, or providing local rigidity to prevent certain kinds of collapse or imbalance, it would get easier. As a practical matter, some magmatter would be used. But it's hard to say exactly how much, because we're talking 'safety margin' here - if active management is done to perfection, it's not needed at all. The question is how close to perfection can it be done?
You could have such a ring made entirely of liquid, and it would be stable until something made a splash or a wave, and started the whole chaotic cascade that would end up, in following decades and centuries, in the whole thing coalescing into separate bodies ranging from planet-sized to black hole, many of them on collision courses with many of the others, and more than a few about to be ejected in random directions from the site.
You need active management of some kind to stop that from happening; a network of maglev tracks running around the thing might keep masses actively moving to maintain balance, concentrate mass where needed for gravitational adjustments, and, via momentum, lend some local rigidity to the structure. This is one of those things that requires minimal energy if done to absolute perfection, but would be extraordinarily hard to do to absolute perfection.
With some magmatter supporting the track, or providing local rigidity to prevent certain kinds of collapse or imbalance, it would get easier. As a practical matter, some magmatter would be used. But it's hard to say exactly how much, because we're talking 'safety margin' here - if active management is done to perfection, it's not needed at all. The question is how close to perfection can it be done?