Abstract: We can learn a great deal about the Universe and the cosmological model by analysing the spatial distribution of the galaxies. I will focus on 3 main topics: 1) the early Universe and isocurvature, 2) testing gravity models and 3) measuring the expansion history of the Universe and probing dark energy. I will briefly review each topic and then discuss some of my recent work that advances these endeavours. 

   Christiano Sabiu gained his doctoral degree from University of Portsmouth, in 2009. After that he was employed as a postdoctoral Research Assistant in University College London till 2012, the KIAS Research Fellow between 2012 and 2014, and became the KASI Research Fellow since 2014. His research interests focuses on the large scale structures in digital sky surveys such as SDSS (BOSS), DES, etc.