 Welcome everyone. I am Ramadevi. I am from Department of Physics IIT Bombay. I am here to teach you group theory methods in physics. So, in day to day lives and in laboratories you do see some arrangements with symmetries ok, some patterns with symmetries. For example, the symmetric arrangements of atoms in a molecule has to be you know has some kind of a pattern which is like ammonia molecule you take or a water molecule you take. You can see that there is some kind of a symmetry pattern. Group theory is a mathematical formulation to understand such symmetries. Understanding complex systems, if you take a complex system it is you can put in a set of mathematical equations. It is not very easy to solve the set of complicated equations and group theory provides you an elegant way of capturing some of the certain details, not all details, but at least certain details of such complex systems. So, the course is for example, if you take a scattering or a decay process of objects of particles, will this process happen? Will this process not happen? Are the questions which you could ask? One way is to go and see in the experiments whether such a scattering process happening or a decay process happening, but what you could do is that from the group theory tools given a symmetry of such a system you can postulate whether these processes are allowed or forbidden ok. In that sense these are certain details which a group theory can actually give you handle on where you do not need to go and solve the complex systems. So, in this course we solve examples and also give you problems as exercises so that you start appreciating the role of group theory tools reproducing some of the experimental observations. I have adopted a presentation style for the audience to learn effortlessly and absorb the group theory arguments which are behind ad hoc postulates and selection rules which you might have seen in some of the courses. So, the contents will be such that you will be able to connect with what you have already learnt or will be learning in courses like particle physics, nuclear physics, atomic molecular physics, quantum mechanics and so on. So, this comprehensive understanding which I am going to give you through this course will actually build a strong foundation and you will be able to take up research in very diverse areas. I hope that you will enjoy this course. The plan of this course is going to be you know you can see them from your group theory arguments using these tools of character table, grade, orthogonality theorem and this exposure will actually train all of you to see how mathematics actually speaks physics. Continuous groups is the other half will be the content of the other half of the semester which is also known as league groups. So, some of the salient things which I am going to discuss during the course are young diagrams, root vectors, weight vectors and so on. And I will briefly you know go over the angle of momentum algebra so that you start understanding the unitary groups concepts and to make this make you people appreciate how elegant the group theory is. I want you to solve or I will take you through the steps of solving hydrogen atom problem where you will be able to see the rigorous elaborate way in which you got the energy spectrum can actually be derived using the tools of group theory in a very elegant fashion and getting all the stationary energy levels. I hope you will enjoy this course.