Aufzählbarkeit, Entscheidbarkeit, Berechenbarkeit: Einführung in die Theorie der rekursiven Funktionen (Heidelberger Taschenbücher, Band 87)

The items bear minimal signs of past use, such as light scratches or memories in the form of markings. These signs of wear give the items a charming character and tell stories of their previous owners, while not affecting their functionality.