ר׳ אריה לייב הכהן הלר

ר׳ אריה לייב בן ר׳ יוסף הכהן הלר (1745–1812), known as the Ketzot after his קצות החושן, was a Galician rabbi and one of the most influential analysts of private law in later Talmudic study. Born in Kalush into a family descended from ר׳ יום טוב ליפמן הלר, he studied under ר׳ משולם איגרא and first served in Rozhniativ. In 1788 he became rabbi of Stryi, remaining there until his death. קצות החושן, published in two parts in 1788 and 1796, probes the conceptual foundations of Choshen Mishpat and transformed the study of monetary law. Its disagreements with נתיבות המשפט by ר׳ יעקב לורברבוים generated משובב נתיבות and a celebrated intertextual debate. שב שמעתתא, first written in youth and published in 1804, analyzes seven clusters of problems concerning doubt, presumption and testimony. אבני מילואים on Even HaEzer was printed posthumously. His works combine close textual argument, conceptual abstraction and practical halakhic consequence; they became central to the analytical curriculum of Lithuanian and other yeshivot.