Jaebum Sohn
Yonsei University · 数学
研究室紹介
Professor Jaebum Sohn's research lab specializes in analytic number theory, with a strong focus on partition functions, continued fractions, and modular forms. The lab explores deep connections between Ramanujan's work—particularly his lost notebook—and modern number theory, emphasizing the theory of $t$-core partitions, simultaneous core partitions, and their combinatorial and arithmetic properties. A central theme is the interplay between partition identities, modular equations, and special functions such as the Rogers–Ramanujan continued fraction and zeta-related continued fractions.
Research Overview
Research Output Trend
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Selected Papers
15In his first two letters to G. H. Hardy and in his notebooks, Ramanujan recorded many theorems about the Rogers–Ramanujan continued fraction. In his lost notebook, he offered several further assertions. The purpose of this paper is to provide proofs for many of the claims about the Rogers–Ramanujan and generalized Rogers–Ramanujan continued fractions found in the lost notebook. These theorems involve, among other things, modular equations, transformations, zeros, and class invariants.
The continued fraction in the title is perhaps the deepest of Ramanujan’s <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="q"> <mml:semantics> <mml:mi>q</mml:mi> <mml:annotation encoding="application/x-tex">q</mml:annotation> </mml:semantics> </mml:math> </inline-formula> -continued fractions. We give a new proof of this continued fraction, more elementary and shorter than the only known proof by Andrews, Berndt, Jacobsen, and Lamphere
On page 45 of his lost notebook, Ramanujan recorded two asymptotic formulas for two continued fractions involving the Riemann zeta-function and Dirichlet L-functions. The paper proves a more general theorem and derives Ramanujan's claims as a corollary of the theorem.
$t$-core partitions have played important roles in the theory of partitions and related areas. In this survey, we briefly summarize interesting and important results on $t$-cores from classical results like how to obtain a generating function to recent results like simultaneous cores. Since there have been numerous studies on $t$-cores, it is infeasible to survey all the interesting results. Thus, we mainly focus on the roles of $t$-cores in number theoretic aspects of partition theory. This inc