Sanghoon Baek
Korea Advanced Institute of Science and Technology · 数学
研究室紹介
Professor Sanghoon Baek's research lab specializes in microbial taxonomy and systematics, with a focus on the isolation, characterization, and phylogenetic classification of novel bacterial species from diverse environments such as ginseng fields and freshwater sediments. The lab employs polyphasic approaches combining 16S rRNA gene sequencing, genomic DNA G+C content analysis, and chemotaxonomic characterization to delineate new taxa within genera like *Brevibacillus*, *Paenibacillus*, and *Novosphingobium*. In parallel, the lab conducts advanced research in algebraic geometry and Galois cohomology, particularly on the essential dimension of central simple algebras and invariants of algebras of low degree and exponent 2. This dual focus bridges microbiology and abstract algebra, reflecting a unique integration of biological and mathematical research.
Research Overview
Research Output Trend
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Selected Papers
15A gram-reaction-positive, rod-shaped, spore-forming bacterium, designated Gsoil 1105(T), was isolated from soil of a ginseng field in Pocheon Province in South Korea and characterized in order to determine its taxonomic position. Comparative analysis of the 16S rRNA gene sequence showed that the isolate belongs to the order Bacillales, showing the highest level of sequence similarity with respect to Tumebacillus permanentifrigoris Eur1 9.5(T) (94.6 %). The phylogenetic distances from other descr
A Gram-positive, rod-shaped, spore-forming bacterium, Gsoil 3088T, was isolated from soil from a ginseng field in Pocheon Province in South Korea and characterized in order to determine its taxonomic position. On the basis of 16S rRNA gene sequence similarity, strain Gsoil 3088T was shown to belong to the family Paenibacillaceae, being related to Brevibacillus centrosporus (96.6%), Brevibacillus borstelensis (96.3%), Brevibacillus parabrevis (96.1%), Brevibacillus formosus (96.1%), Brevibacillus
A yellow-pigmented, Gram-negative, short rod-shaped, non-motile and non-spore-forming bacterial strain, designated HU1-AH51(T), was isolated from freshwater sediment and was characterized using a polyphasic approach, in order to determine its taxonomic position. On the basis of 16S rRNA gene sequence similarity, strain HU1-AH51(T) was shown to belong to the genus Novosphingobium, showing the highest level of sequence similarity with respect to Novosphingobium resinovorum NCIMB 8767(T) (96.0 %),
A Gram-positive, aerobic or facultatively anaerobic, rod-shaped, spore-forming bacterium, strain Gsoil 1138(T), was isolated from soil of a ginseng field in Pocheon Province, South Korea, and was characterized in order to determine its taxonomic position. On the basis of 16S rRNA gene sequence analysis, strain Gsoil 1138(T) was shown to belong to the family Paenibacillaceae and was most closely related to the type strains of Paenibacillus chondroitinus (98.2 % similarity) and Paenibacillus algin
Let p be a prime integer, 1≤s≤r be integers and F be a field of characteristic different from p. We find upper and lower bounds for the essential p-dimension edp($ Al{{g}_{{{{p}^r},{{p}^s}}}} $) of the class $ Al{{g}_{{{{p}^r},{{p}^s}}}} $ of central simple algebras of degree pr and exponent dividing ps. In particular, we show that ed(Alg8,2)=ed2(Alg8,2)=8 and edp($ Al{{g}_{{{{p}^2},p}}} $)=p2+p for p odd.
We determine the group of invariants with values in Galois cohomology with coefficients $${\mathbb{Z}/2\mathbb{Z}}$$ of central simple algebras of degree at most 8 and exponent dividing 2.
A Gram-negative, motile, non-spore-forming bacterial strain, designated HU1-GD12(T), was isolated from freshwater sediment. The strain was characterized by using a polyphasic approach in order to determine its taxonomic position. Comparative analysis of the 16S rRNA gene sequence showed that the isolate constituted a distinct branch within the genus Sphingobium, showing the highest level of sequence similarity with respect to Sphingobium ummariense RL-3(T) (96.2 %). Strain HU1-GD12(T) had a geno
Let p be a prime integer. For any integers <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>1</mml:mn> <mml:mo>⩽</mml:mo> <mml:mi>s</mml:mi> <mml:mo>⩽</mml:mo> <mml:mi>r</mml:mi> </mml:math> , <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mtext/> <mml:mrow> <mml:msup> <mml:mi>p</mml:mi> <mml:mi>r</mml:mi> </mml:msup> <mml:mo>,</mml:mo> <mml:msup> <mml:mi>p</mml:mi> <mml:mi>s</mml:mi> </mml:msup> </mml:mrow> </mml:ms
We study the semi-decomposable invariants of a split semisimple group and their extension to a split reductive group by using the torsion in the codimension <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="2"> <mml:semantics> <mml:mn>2</mml:mn> <mml:annotation encoding="application/x-tex">2</mml:annotation> </mml:semantics> </mml:math> </inline-formula> Chow groups of a product of Severi-Brauer varieties. In particular, for any <inline
Consider a crystallographic root system together with its Weyl group $W$ acting on the weight lattice $M$. Let $Z[M]^W$ and $S^*(M)^W$ be the $W$-invariant subrings of the integral group ring $Z[M]$ and the symmetric algebra $S^*(M)$ respectively. A celebrated theorem of Chevalley says that $Z[M]^W$ is a polynomial ring over $Z$ in classes of fundamental representations $w_1,...,w_n$ and $S^*(M)^{W}$ over rational numbers is a polynomial ring in basic polynomial invariants $q_1,...,q_n$, where $
Let 1⩽m⩽n be integers with m|n and Algn, m the class of central simple algebras of degree n and exponent dividing m. In this paper, we find new, improved upper bounds for the essential dimension and two-dimension of Algn, 2. In particular, we show that ed2(Alg16, 2)=24 over a field F of characteristic different from 2.
In the present paper, we provide a uniform bound for the annihilators of torsion of Chow groups of the variety of Borel subgroups of a strongly inner linear algebraic group of orthogonal type.
In this article, we present semiorthogonal decompositions for twisted forms of grassmannians.
Let G be a split semisimple linear algebraic group over a field and let X be a generic twisted flag variety of G . Extending the Hilbert basis techniques to Laurent polynomials over integers we give an explicit presentation of the Grothendieck ring K_0(X) in terms of generators and relations in the case G=G^{sc}/\mu_2> is of Dynkin type A or C (here G^{sc} is the simply-connected cover of G ); we compute various groups of (indecomposable, semi-decomposable) cohomological invariants of degree