Group 6

J symbol (comma-dot):  ,.

Monadic case:

Name: item-ravel

Rank: _ (infinite/unbounded) – applies to the entire array y

Definition (simple): ,. y ravels the items of y (i.e. converts each item of y to a vector/list).

Definition (precise): ,. y if y is an atom/scalar then ,. y is 1 1 $y (i.e. a matrix with one element); otherwise it is a matrix whose rows are the vectors formed by ravelling the items of y.

Please also include explanations for your answers to some of the following questions:

What is the item-ravel of a scalar, vector, matrix, rank-3 array?

What is the item-ravel of an empty list?

Dyadic case:

Name: stitch

Rank: _ (left); _ (right) – applies to the entire array on the left and right hand side

Definition: x ,. y the items of x and stitched to the corresponding items of y.

Please also include explanations for your answers to some of the following questions:

What is the stitch of two scalars, vectors, matrices?

What is the stitch of a scalar with a vector, vector with a matrix, etc?

What can x and y not be stitched?