NB. J Phrases Section 9B. Linear Vector Functions

a0=: MR=: 1 : 'x.@=@i.@#' NB. Matrix representation of linear function
d1=: mp=: +/ . *          NB. Matrix product
a2=: L=: &mp              NB. Linear function represented by matrix
a3=: inv=: ^:_1           NB. Inverse adverb
a4=: MRI=: (^:_1) 'MR' f. NB. Matrix representation of inverse function
a5=: MR (%.@)             NB. "
