Operator theory is an important part of the theory of functional analysis,arising in early twentieth century.It has applied in many areas,such as:matrix theory,control theory,statistics and so on.As a part of operator theory,Young inequality is simple but important.And it has attracted many researchers in the field,where adding a positive term to the left side is possible.In recent decades,more and more results about Young inequality are presented.Fol-lowing this way,we can do further work on it.In this work,we mainly give refinements and reverses of Young and Young type in-equality.Besides,some results of Heron mean and harmonic-geometric-arithmetic mean are presented too.The main work contains the following topics:1.We prove several multi-term refinements of Young and Young type inequalities with Kantorovich constant for both real numbers and matrices.Then,we will give the refinements of Young inequalities for operators and matrix with a different method based on others' results.2.The relationship between Heron mean and arithmetic-geometry-harmonic mean are studied,and some results about Heron mean are given.3.Some results of harmonic-geometric-arithmetic mean will be improved and inequal-ities in the form of operators,matrices and determinants corresponding to them are given. |