论文标题
唯一不贵的CRDT是计数器
The Only Undoable CRDTs are Counters
论文作者
论文摘要
在比较代表可以成长和收缩的集合的众所周知的CRDT时，我们发现了警告。在一个中，无法可靠地撤消元素的去除。在另一个中，不良状态是可以实现的，例如当一个元素存在-1次时（必须添加以使集合变得空的）。第一个缺乏通用的撤消，而第二个表现不像一组，而更像是元组的元素，每个可能的元素。 使用某种群体理论，我们表明这种权衡是不可避免的：每个不可拨的CRDT都是元组的元组。
In comparing well-known CRDTs representing sets that can grow and shrink, we find caveats. In one, the removal of an element cannot be reliably undone. In another, undesirable states are attainable, such as when an element is present -1 times (and so must be added for the set to become empty). The first lacks a general-purpose undo, while the second acts less like a set and more like a tuple of counters, one per possible element. Using some group theory, we show that this trade-off is unavoidable: every undoable CRDT is a tuple of counters.
