{"id":"no-high-key-fence","text":"No node stores a high-key (upper-bound fence key); searchers cannot detect mid-split state, which would be required for Lehman & Yao's concurrent search protocol","truth_value":"IN","source":"entries/2026/05/29/topic-lehman-yao-1981.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"explanation":{"steps":[{"node":"no-high-key-fence","truth_value":"IN","reason":"premise"}]}}