Combinators, -Terms and Proof Theory

Focusing on pure combinatory logic, this monograph explores foundational ideas and their implications in proof theory, alongside the author's original contributions. Revised content from previous notes is presented, correcting earlier inaccuracies. The author acknowledges significant influences from scholars such as Stig Kanger, Per Martin-Löf, Dag Prawitz, and W. W. Tait, as well as feedback from Craig McKay. The work reflects a collaborative spirit while underscoring the author's responsibility for any shortcomings.