The Medical Center Hospital Authority claimed that its leasehold interest in a privately owned continuing-care facility was public property exempt from ad valorem taxation. The trial court granted summary judgment to the Authority, and the Court of Appeals treated earlier bond-validation orders as conclusive on ownership and taxability. The Supreme Court of Georgia held that bond-validation judgments are conclusive only on matters actually referenced and adjudicated in those proceedings. The earlier orders addressed the public purpose of the bonds, but they did not decide whether the Authority’s leasehold was public property for tax purposes. That question instead requires applying the separate standard governing whether a public instrumentality holds property for the State and public rather than for private gain. The court reversed and remanded for the superior court to decide taxability independently, while permitting it to consider relevant materials from the bond proceedings.