| m0=: I=: =@i.@# | Identity matrix of order of y |
| m1=: inv=: %. | Matrix inverse |
| d2=: mq=: %. | Matrix quotient |
| d3=: mp=: +/ . * | Matrix product |
| d4=: amp=: -/ . * | Alternating matrix product |
| m5=: det=: -/ . * | Determinant |
| d6=: fit=: {:@] %. {.@] ^/ i.@[ | d fit x,:f x is coeffs of pn fit of degree d-1 |