Comparing infinite sets — a process of abstraction

摘要: Abstract This paper describes a research-based teaching interview, aimed at encouraging an especially talented student, Ben, to reflect on his thinking about infinite quantities. We designed the interview with intention that Ben would use two incompatible methods for comparing sizes of sets. In this paper, we examine Ben’s reactions ensuing contradiction. responses are analyzed reference model abstraction based three dynamically nested epistemic actions constructing, recognizing and building-with.