LINEAR PRESERVERS OF ACU-MAJORIZATION ON R³ AND M3,m

In this note, we present an equivalent condition for linear preservers of group majorization induced by closed subgroup G of O(Rn). Moreover, a new concept of majorization is defined on R³ as acu-majorization and this is extended for 3×m matrices. Then we characterize all its linear preservers on R³ and M3,m.