This data structure comes from the Wikipedia page on mutual recursion, which itself cites course notes from an introduction to Standard ML by Robert Harper. I am not aware of practical reasons to choose this particular representation of trees over the alternatives, other than as an illustration of a language’s ability to support mutually recursive data. I find it unwieldy, which is why I chose to use it for this post.2
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翟美卿：这一调整说明市场已度过较困难阶段，政策目标转向巩固企稳成果，防范波动风险，稳定市场预期。，详情可参考新收录的资料
Index Cond: (message_fts @@ '''research'' & ''team'''::tsquery)
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