This paper presents a class of epistemic logics that captures the dynamics of acquiring knowledge and descending into oblivion, while incorporating concepts of group knowledge. The approach is grounded in a system of weighted models, introducing an ``epistemic skills'' metric to represent the epistemic capacities tied to knowledge updates. Within this framework, knowledge acquisition is modeled as a process of upskilling, whereas oblivion is represented as a consequence of downskilling. The framework further enables exploration of ``knowability'' and ``forgettability,'' defined as the potential to gain knowledge through upskilling and to lapse into oblivion through downskilling, respectively. Additionally, it supports a detailed analysis of the distinctions between epistemic de re and de dicto expressions. The computational complexity of the model checking and satisfiability problems is examined, offering insights into their theoretical foundations and practical implications.

翻译：本文提出了一类认知逻辑，用以刻画获取知识与陷入遗忘的动态过程，同时融入了群体知识的概念。该方法基于加权模型系统，引入"认知技能"度量指标，以表征与知识更新相关的认知能力。在此框架下，知识获取被建模为技能提升的过程，而遗忘则被表现为技能下降的结果。该框架进一步支持对"可知性"与"可遗忘性"的探究，分别定义为通过技能提升获得知识的潜力和通过技能下降陷入遗忘的可能性。此外，它还能对认知的殊型与殊相表达式进行细致区分。本文还考察了模型检测与可满足性问题的计算复杂性，揭示了其理论基础与实践应用价值。