Query Auto-Completion(QAC), as an important part of the modern search engine, plays a key role in complementing user queries and helping them refine their search intentions.Today's QAC systems in real-world scenarios face two major challenges:1)intention equivocality(IE): during the user's typing process,the prefix often contains a combination of characters and subwords, which makes the current intention ambiguous and difficult to model.2)intention transfer (IT):previous works make personalized recommendations based on users' historical sequences, but ignore the search intention transfer.However, the current intention extracted from prefix may be contrary to the historical preferences.

翻译：查询自动补全（Query Auto-Completion, QAC）作为现代搜索引擎的重要组成部分，在补充用户查询并帮助其优化搜索意图方面发挥着关键作用。现实场景中的QAC系统面临两大挑战：1）意图模糊性（Intention Equivocality, IE）：在用户输入过程中，前缀常包含字符与子词的组合，使得当前意图难以明确建模；2）意图转移（Intention Transfer, IT）：现有方法基于用户历史序列进行个性化推荐，却忽略了搜索意图的转移。然而，从前缀中提取的当前意图可能与历史偏好相悖。