This book constitutes refereed proceedings of the 20th International Conference on Mathematical Optimization Theory and Operations Research, MOTOR 2021, held in Irkutsk, Russia, in July 2021. Due to the COVID-19 pandemic the conference was held online. The 31 full papers and 3 short papers presented in this volume were carefully reviewed and selected from a total of 102 submissions. The papers in the volume are organised according to the following topical headings: continuous optimization; integer programming and combinatorial optimization; operational research applications; optimal control.

Andrei Orlov examines early Christological developments in the light of rabbinic references to the "two powers" in heaven, tracing the impact of this concept through both canonical and non-canonical material. Orlov begins by looking at imagery of the "two powers" in early Jewish literature, in particular the book of Daniel, and in pseudepigraphical writings. He then traces the concept through rabbinic literature and applies this directly to understanding of Christological debates. Orlov finally carries out a close examination of the "two powers" traditions in Christian literature, in particular accounts of the Transfiguration and the Baptism of Jesus. Including a comprehensive bibliography listing texts and translations, and secondary literature, this volume is a key resource in researching the development of Christology.

The essays collected in Watering the Garden are intended to honor Deirdre Dempsey, a distinguished biblical educator, translator, and scholar. The contributions to this Festschrift mirror Dempsey’s own scholarly interests, including biblical studies, with particular attention to the Old Testament and intertestamental literature, the theology of visual arts, the history of spiritual traditions, and modern theology. The content of the Festschrift closely follows Dempsey's own spiritual and scholarly journey and reflects the breadth and scope of her influence on the academy.

The essays collected in Revelation and Leadership in the Kingdom of God intend to honor Professor Ian Arthur Fair, a distinguished biblical scholar and leader in Christian education, known for his groundbreaking research on the Book of Revelation and church leadership. Scholarly contributions included in the Festschrift mirror Fair's own scholarly interests, including biblical studies, with particular attention to the New Testament apocalyptic traditions, philosophy of missions, theology of worship, history of the Restoration movement, and modern theology. The content of the Festschrift thus closely follows Fair's own spiritual and scholarly journey and also reflects the breadth and scope of his influence on the church and the academy.

Andrei Orlov examines early Christological developments in the light of rabbinic references to the "two powers" in heaven, tracing the impact of this concept through both canonical and non-canonical material. Orlov begins by looking at imagery of the "two powers" in early Jewish literature, in particular the book of Daniel, and in pseudepigraphical writings. He then traces the concept through rabbinic literature and applies this directly to understanding of Christological debates. Orlov finally carries out a close examination of the "two powers" traditions in Christian literature, in particular accounts of the Transfiguration and the Baptism of Jesus. Including a comprehensive bibliography listing texts and translations, and secondary literature, this volume is a key resource in researching the development of Christology.