## Alexander Wendland (19/02/18)

Math Colloquium

### Speaker: Alexander Wendland, University of Warwick

### Title: Facially restricted graph colouring’s

Location: HB-5 (Háskólabíó)

Time: Monday 19 February at 10:50

### Abstract:

Arguably one of the best known theorems from combinatorics is the four colour theorem, stating that every planar graph can be coloured using at most four colours such that no edge connects two vertices of the same colour. In this talk I will discus variants on this theorem in particular list colouring’s and facial restriction’s on the colouring. In this, I present the method of discharging in Graph Theory, used to finally prove the four colour theorem nearly 140 years after it was first stated, which has been used to prove theorems elsewhere in Mathematics.