Are you saying the (single hop) IS_A_REPLY_TO relationship is unnecessary because the two events are already connected by the (two hop) path, that traverses the NostrEventTag node? This is a fair point. It would be a tradeoff: the reply_to relationship makes the db bigger, but a search for a single-hop path will always be more performant than a multi-hop path. It might be a scenario where it’s worth adding the extra path if we think there’s a high likelihood we’re going to want to fetch that thread. I could even envision scenarios where stale relationships like this get pruned if they’re old and unlikely to be needed, the goal being to decrease the footprint of the graph.