Title: Bubbling Phenomenon of Harmonic Maps

Abstract: In 1981, Sacks and Uhlenbeck proved a surprising result that in any compact manifold we can always find an immersed minimal 2-sphere. Their method is finding a harmonic sphere. In their proof they found an interesting phenomenon called "bubbling", and it turns out to be an very common and important phenomenon in geometry and pdes. In this talk I will discuss this interesting phenomenon.