### Professor Leonid Lerer

#### 1943 - 2014

Professor Leonid Lerer was born on April 19, 1943 in the USSR. Leonid got his Ph.D. under the guidance of I. Gohberg and A. Markus, in 1969. From 1969 to 1973 he was a Lecturer at Kishinev State University, and in 1973 he was laid off due to his application to immigrate to Israel. He came to Israel in December 1973 and to the Technion in 1974. In 1988 he became a Full Professor.

Leonid was a leading expert in Operator Theory, Systems Theory, Functional Analysis and Linear Algebra. Among his distinguished collaborators are I. Gohberg, M.A. Kaashoek, P. Lancaster, A. C. M. Ran, L. Rodman and H. Woerdeman.

Leonid contributed in a significant way to the spectral theory of matrix and operator functions, and the theory of Wiener-Hopf operators. His research points out to the links between Systems Theory and Wiener-Hopf operators. In collaboration with his students he introduced the so called Bezout operators for various matrix functions.

Leonid authored about 80 papers in scientific journals. He served on the editorial board of "Integral Equations and Operator Theory" since its foundation in 1977, as well as special volumes. He was awarded several research grants, including BSF and ISF grants.

Leonid played an active role in the academic life of our department. He supervised five M.Sc. and six Ph.D. theses. He was a member of the organizing committee of several of the Haifa Matrix Theory Conferences, and contributed to their great success, thus enhancing the Technion's reputation in the world.

Leonid's stature in the scientific community is evidenced by the volume "Advances in structured operator theory and related areas", in the series "Operator Theory: Advances and Applications", Volume 237. This volume, published by Birkhäuser, is dedicated to Leonid's 70th birthday, and is declared as the "Leonid Lerer Anniversary Volume". Leonid was fortunate to get this volume before he passed away on January 2, 2014.

שלושה דברים בחייו היו חשובים לו יותר מכל: משפחתו, המדינה שלו והמתמטיקה. לאוניד היה בעל, אב וסבא אוהב אשר השאיר אחריו אישה - ברכה, לה היה נשוי יותר מ-50 שנה ושתי בנות - חני וספירה. מהכרות ראשונית עם לאוניד ניתן היה לראות שהיה אדם חושב, מעמיק וחוקר - איש מדע. אך אלה שזכו להכירו יותר לעומק גילו בנוסף לכך, אדם איכפתי, רגיש ורוחני אשר ידע לשלב את כל אלו בחייו האישיים ובעבודתו.

יהי זכרו ברוך !