What is the difference between LSI and LIS. How does both help us in seo concepts. Do we implement it practically or else we will learn only the concept
One of the definitions of LSI is a latent semantic indexing. This is mathematical technique of dimension reduction. In text processing it allows to find most valuable keywords for topics in bunch of texts. Topics are created by algorithm. Details you can find on wikipedia. In case of seo well trained LSI model can help to find related keywords that are not obvious for your text or set of keywords - so fro example you can extend your semantic core. And what is LIS I have no idea.