Matriz 1-dimensional se cambia a un vector en R

> a<-matrix(c(1:9),3,3) > a [,1] [,2] [,3] [1,] 1 4 7 [2,] 2 5 8 [3,] 3 6 9 > a[3,]*a[,3] # I expect 1x1 matrix as result of this. [1] 21 48 81 > class(a) [1] "matrix" > class(a[3,]) [1] "integer" En R, la matriz unidimensional se cambia a un ...