Two ways light can refocus in curved spacetime turn out to differ

In general relativity, a spacetime is 'refocusing' if all light rays from any point reconverge somewhere — a strong geometric constraint. This paper proves that refocusing does not imply the stronger version of this property, settling an open question and showing the two conditions are genuinely distinct. The result clarifies the structure of causal geometry and introduces a new intermediate notion that does force the stronger property.