## Department Seminars and Colloquium

#### Michael G. Dobbins (KAI-X (Binghamton University))Etc.

MacPhersonians and Combinatorial Grassmannians

#### Geon Ho Choe (KAIST)Colloquium

Discrete Girsanov Theorem and Asymptotic Martingale Theory for Option Pricing

#### Woocheol Choi (Dept. of Math., Sungkyunkwan University)ACM Seminars

Distributed optimization: Theory of algorithms and applications

#### 이상훈 (고등과학원)Differential Geometry

Liouville-type theorems for adapted metrics of upper half-plane model of hyperbolic space

#### 엄태현 (KAIST)PH.D Defence

Computing the density of tautologies in propositional logic by solving system of quadratic equations of generating functions

## Graduate Seminars

## SAARC Seminars

## IBS-KAIST Seminars

#### Stephanie Nivoche (Cote d’Azur University, Nice, France)Algebraic Geometry

Behaviour of multipoled pluricomplex Green's functions in connection with algebraic geometry problems

#### Ben Lund (IBS Discrete Mathematics Group)Discrete Mathematics

Almost spanning distance trees in subsets of finite vector spaces

## Conferences and Workshops

## Student News

## Bookmarks

## Research Highlights

## Bulletin Boards

##
## Problem of the week

Consider a function \(f: \{1,2,\dots, n\}\rightarrow \mathbb{R}\) satisfying the following for all \(1\leq a,b,c \leq n-2\) with \(a+b+c\leq n\).

\[ f(a+b)+f(a+c)+f(b+c) - f(a)-f(b)-f(c)-f(a+b+c) \geq 0 \text{ and } f(1)=f(n)=0.\]

Prove or disprove this: all such functions \(f\) always have only nonnegative values on its domain.

Acknowledgement: This problem arises during a research discussion between June Huh, Jaehoon Kim and Matt Larson.

Consider a function \(f: \{1,2,\dots, n\}\rightarrow \mathbb{R}\) satisfying the following for all \(1\leq a,b,c \leq n-2\) with \(a+b+c\leq n\).

\[ f(a+b)+f(a+c)+f(b+c) - f(a)-f(b)-f(c)-f(a+b+c) \geq 0 \text{ and } f(1)=f(n)=0.\]

Prove or disprove this: all such functions \(f\) always have only nonnegative values on its domain.

Acknowledgement: This problem arises during a research discussion between June Huh, Jaehoon Kim and Matt Larson.