The 12th KIAS Combinatorics Workshop
Korea Institute for Advanced Study, Seoul, Korea June 03–04, 2016
Information Title: The 12th KIAS Combinatorics Workshop Date: June 03 - 04, 2016 Venue: 1503, KIAS Web: http://home.kias.re.kr/MKG/h/Combinatorics/
Invited Speakers Andreas Holmsen (KAIST) Woong Kook (Seoul National University) Young Soo Kwon (Yeungnam University) Suil O (Simon Fraser University, Canada) Se-jin Oh (Ewha Womans University) Heesung Shin (Inha University)
Organizers Sung-Tae Jin (KIAS) Jang Soo Kim (Sungkyunkwan Univ.) Jeong Han Kim (KIAS) Seog-Jin Kim (Konkuk Univ.) Young Soo Kwon (Yeungnam Univ.) Sang June Lee (Duksung Women’s Univ.) Boram Park (Ajou Univ.) Seunghyun Seo (Kangwon Nat’l Univ.)
or
kcws.combinatorics.kr
Timetable June 03 (Friday) 13:40 – 14:15
Registration
14:15 – 14:20
Opening Address
14:20 – 18:00
Session (A)
Chair: 14:20 – 15:00
Woong Kook
15:10 – 15:50
Heesung Shin
16:00 – 17:00
Coffee Break and discussion
17:00 – 17:40 18:00 -
Andreas Holmsen
Combinatorial Interpretations for harmonic classes Enumerations of vertices among all rooted ordered trees with levels
The intersection of a matroid and an oriented matroid
Banquet (용성)
June 04 (Saturday) 9:20 – 12:00
Session (B)
Chair: 9:20 – 10:00
Young Soo Kwon
10:00 – 10:30
Coffee Break
10:30 – 11:10
Suil O
11:20 – 12:00
Se-Jin Oh
12:00 –
Closing
Skew morphisms and regular Cayley maps
Interlacing families and the Hermitian spectral norm of digraphs Commutation classes and Catalan triangle
June 03, Talk 1
Woong Kook
Speaker: Woong Kook Affiliation: Seoul National University Title: Combinatorial Interpretations for harmonic classes Abstract Combinatorial Hodge theory states that the kernel of combinatorial Laplace operators and the homology of a given complex over a field are isomorphic as vector spaces, and the elements of that kernel are called harmonic classes. In this talk we will discuss combinatorial interpretations for the harmonic classes of a homology circle, i.e., a complex having the same homology as a circle.
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June 03, Talk 2
Heesung Shin
Speaker: Heesung Shin Affiliation: Inha University Title: Enumerations of vertices among all rooted ordered trees with levels Abstract In this talk, we enumerate the cardinalities and give bijections for the following four sets of vertices among all rooted ordered trees of a fixed size: (i) all first children of degree k at level `, (ii) all non-first children of degree k at level ` − 1, (iii) all leaves having k − 1 elder siblings at level `, and (iv) all non-leaves of outdegree k at level ` − 1. Our results unite and generalize several previous works in the literature.
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June 03, Talk 3
Andreas Holmsen
Speaker: Andreas Holmsen Affiliation: KAIST Title: The intersection of a matroid and an oriented matroid Abstract An oriented matroid is a combinatorial abstraction of real vector configurations. I will present an intersection theorem where we are intersecting a matroid and an oriented matroid defined on the same ground set. This can be viewed as a combinatorial generalization of Barany’s ”colorful caratheodory theorem” from 1982.
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June 04, Talk 4
Young Soo Kwon
Speaker: Young Soo Kwon Affiliation: Yeungnam University Title: Skew morphisms and regular Cayley maps Abstract A skew morphism of a group G which is a generalization of a group automorphism appears naturally in a product of G and some cyclic group. In this talk, some properties of skew morphism will be dealt with. Furthermore, we will consider some relations between skew morphisms and Cayley maps. Finally we deal with classification of regular Cayley maps on dihedral groups. This is a joint work with Istvan Kovacs.
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June 04, Talk 5
Suil O
Speaker: Suil O Affiliation: Simon Fraser University, Canada Title: Interlacing families and the Hermitian spectral norm of digraphs Abstract Recently, Marcus, Spielman, and Srivastava proved the existence of infinite families of bipartite Ramanujan graphs of every degree at least 3 by using the method of interlacing families of polynomials. In this talk, we apply their method to prove that for any connected graph G, there exists an orientation of G such that the spectral radius of the corresponding Hermitian adjacency matrix is at most that of the universal cover of G.
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June 04, Talk 6
Se-Jin Oh
Speaker: Se-Jin Oh Affiliation: Ewha Womans University Title: Commutation classes and Catalan triangle Abstract In this talk, I will introduce the notion of commutation class of reduced expressions for finite Weyl groups and the relationship with Catalan triangle numbers and binomial coefficient. In the aspect of representation theory, the number of reduced expressions of fully commutative element appears as the dimension of homogeneous module over KLR-algebra. Interestingly, the number of reduced expressions of fully commutative element is closely related to number of (skew) Young tableaux.
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KIAS Campus Map
Building 1 • B1 fl. Fitness Rom • 1st fl. Entrance A, B,Lobby, Auditorium, International Conference Hall • 2nd fl. President’s Office, Faculty Offices, Administrative Offices • 3rd fl. Faculty Offices, Meeting Room, Administrative Offices • 4th fl. Seminar Rooms, Library, Discussion Room, Research Fellow Offices • 5th fl. Seminar Rooms, Faculty Offices, Research Fellow Offices, Visitors Offices Building 7 • 3rd fl. Entrance C, Administrative Offices, Discussion Room, Seminar Room Union Building • 1st fl. Table Tennis Court • 2nd fl. Cafeteria (Korean food), Dispensary, Infirmary • 3rd fl. Woori Bank, Post Office, Convenience Store, Copy room, Bookstore • 4th fl. Cafeteria (Korean food) SUPEX (Building 2) • 2nd fl. Cafe ”Atrium” (Western food)
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Dinner Place Dinner on June 03 Place: Yongsung (It takes 10 minutes from KIAS to the dinner place on foot.)
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List of Participants ∗
Last Name
First Name
Affiliation
Email
1
Boram
Park
Ajou University
[email protected]
2
Chin
Wooyoung
*
KAIST
[email protected]
3
Cho
Minho
*
KAIST
[email protected]
*
4
Choi
Hojin
5
Dickson-Uka
Stephen Eke
6
Eom
Taehyun
*
KAIST
[email protected]
7
Eur
Christopher
*
UC Berkeley
[email protected]
8
Galvez
Lucky Erap
*
Sogang University
[email protected]
9
Hong
Kyungpyo
NIMS
[email protected]
10
Hwang
Byung-hak
11
Hyun
Jong Yoon
12
Jin
Sung-Tae
*
KAIST
[email protected]
The Mentor Initiative
[email protected]
Seoul National University
[email protected]
KIAS
[email protected]
KIAS
[email protected]
Pohang University of Science and 13
Jineon
Baek
Technology
14
Jung
Ji-Hwan
Sungkyunkwan University
[email protected] [email protected]
15
Kang
Dongyeap
*
KAIST
[email protected]
16
kim
jong tak
*
yeungnam university
[email protected]
17
Kim
Jong Woo
*
Korea University
[email protected]
18
Kim
Hyun Kwang
Pohang University of Science & Technology
[email protected]
19
Kim
Hyoungjun
Korea University
[email protected]
20
Kim
Hana
NIMS
[email protected]
21
Kim
Byungchan
SeoulTech
[email protected]
22
Kim
Jinha
23
Kim
Ilhyung
24
Kim
Younjin
25
Kim
Minki
26
Kim
Sangwook
27
Kim
28
Kim
29
*
*
*
Seoul National University
[email protected]
Seoul National University
[email protected]
Ewha Womans University
[email protected]
KAIST
[email protected]
Chonnam National University
[email protected]
Jang Soo
SKKU
[email protected]
Seog-Jin
Konkuk University
[email protected]
Kwang Ju
Choi
Ewha Womans University
[email protected]
30
Kwon
Young Soo
Yeungnam University
[email protected]
31
Lee
Kang-Ju
*
Seoul National University
[email protected]
32
Lee
Jooho
*
KAIST
[email protected]
33
Lee
Seung Jin
KIAS
[email protected]
34
lee
kyung tae
Konkuk University
[email protected]
35
Lee
Sanha
*
Sungkyunkwan University
[email protected]
36
Lee
Nari
*
Sogang University
[email protected]
37
Lee
Kyoung Ja
Hannam University
[email protected]
38
Lee
Sang-Jin
Konkuk University
[email protected]
9
: student
39
Lee
Sang June
Duksung Women`s Univ
40
Na
Joohan
KIAS
[email protected] [email protected]
41
No
Sungjong
Ewha Womans University
[email protected]
42
O
Suil
Simon Fraser University
[email protected]
43
Oh
Seungsang
Korea University
[email protected] [email protected]
44
Oh
Se-jin
Ewha Womans University
45
Oum
Sang-il
KAIST
[email protected]
46
Park
Jihye
Yeungnam University
[email protected]
47
Park
Jongyook
KIAS
[email protected]
48
Rho
Yoomi
Incheon nat'l University
[email protected]
49
Roe
Young Gun
*
Sogang University
[email protected]
50
Seo
Jeong-woo
*
Yeungnam University
[email protected]
51
Shin
Heesung
Inha University
[email protected]
52
Sun-Young
Nam
KIAS
[email protected]
53
Tran
Nam Trung
Institute of Mathematics, VAST, Vietnam; and KIAS research visitor
[email protected]
Do
Institute of Mathematics, Hanoi, Vietnam
[email protected]
Konkuk University
[email protected]
54 Trong Hoang
*
55
Yeo
Yong-Dong
*
56
Yoo
Kang-min
*
KAIST
[email protected]
57
Yoo
Hyung Ki
*
Korea University
[email protected]
58
Yun
Sun mi
*
Sungkyunkwan University
[email protected]
10
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