The document discusses two ways in which proprietary interests in land can become fragmented: 1. Fragmentation by system - when native title rights come into collision with the Australian system of landholding, native title is easily extinguished. 2. Fragmentation by time - through the doctrine of estates, which allows for the creation of life estates and future interests like remainders that divide ownership of land over time. Estates can be further fragmented by conditions and limitations. The rule against perpetuities aims to limit how far into the future fragmentation by future interests can extend by requiring interests to vest within a certain period. Additionally, fragmentation occurs between legal and equitable interests and those defined by common law, equity, and statute.