You see inequalities in any discipline. In math-fin area specifically, most of the times, the inequalities are derived from a basic set of inequalities such as Cauchy’s, AM-GM, Jensen’s,Holder’s, Minkowski’s Inequalities. One typically comes across inequalities in some math course where one is asked to prove a specific inequality. Typically one solves them just like one learns the grammar and syntax of a language. Sadly ,the principles behind them are conveniently forgotten as one does not actually use then in some practical context.