The third annual International Applied Category Theory Conference (ACT2020) was planned to take place at MIT in Cambridge, Massachusetts USA. However, the global COVID-19 pandemic made the prospect of holding a large in-person meeting impossible, and the event was thus held completely online. Holding the talks online had the new benefits of reducing carbon footprint, being inclusive of people from more parts of the world, and producing higher-quality video talks, which have been posted online for posterity. The ACT2020 contributions spanned a broad spectrum of application areas, including databases, dynamical systems, functional programming, game theory, lenses, neuroscience, probabilistic programming, natural language processing, quantum mechanics, and cyberphysical systems. Papers featured a broad range of categorical techniques. Papers in this Proceedings volume represents about half of the talks presented at ACT2020. Being included in the proceedings vs. not is not an indication of talk quality, but instead almost exclusively the choice of the authors, e.g. to present work already published elsewhere.

中文翻译：

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2020年第三届国际应用类别理论年会论文集

第三届年度国际应用类别理论会议（ACT2020）计划在美国麻萨诸塞州剑桥市的MIT举行。但是，全球COVID-19大流行使得不可能举行大型的面对面会议，因此该活动完全在线进行。在线举行讲座具有减少碳足迹，包容来自世界各地的人们的新优势，并制作了更高质量的视频讲座，已在网上发布以供后代使用。ACT2020的贡献涵盖了广泛的应用领域，包括数据库，动力学系统，功能编程，游戏理论，镜头，神经科学，概率编程，自然语言处理，量子力学和网络物理系统。论文采用了广泛的分类技术。会议论文集的论文约占ACT2020演讲的一半。被包括在诉讼程序中或不包括在内，并不表示讲话质量，而是几乎完全由作者选择，例如展示已经在其他地方发表的作品。