So, here what we have talked by now in this lecture, I have already talked about the equation of continuity by now I will just summarize. I have talked about equation of continuity we have talked about equation of continuity, then we have talked about some of the characteristic motion that is irrotational irrotational flow and then the flow is irrotational. And the fluid incompressible we call this as a potential flow, I will just summarize all this things in this lecture.