The base-point-free conjecture for nef line bundles on projective Calabi–Yau varieties

Let $X$ be a projective Calabi–Yau variety, and let $L$ be a nef line bundle on $X$. A line bundle is semiample if some positive tensor power is generated by its global sections.

Base-point-free conjecture. If $L$ is nef, then $L$ is semiample.

This extends the base-point-free theorem from good or nef and big line bundles to all nef line bundles on projective Calabi–Yau varieties. The source presents it as a well-known conjecture; no resolution is given here.