The 12th International Congress of Logic, Methodology and Philosophy of Science was held in Spain, and at least one of Prof  Hacker, Prof  Maas and Prof  Reger attended the conference  Known: (1) Those who sign up for the conference must submit an English academic paper, and the invitation letter will be issued after expert review  (2) If Prof  Hacker attends this conference, then Prof  Maas must attend  (3) Prof
Reger submitted a German academic paper to the conference
Prof. Reger attended the conference.