Every open gap on this site, in one place. A gap is published only if knowing the answer would change our understanding of the subject. Absence is the finding.
One open gap · one ring each, in the column of its kind · a solid ring is a gap that closedOne open gap · one ring each, in the column of its kind · a solid ring is a gap that closed
0 closed
No gap of this kind is open. That is a fact about the record, not about the world.