m/  (Adverb)

INSERT (_)  If m is a gerund, then m/y inserts successive verbs from m between items of y. Thus, +`*/i.6 is 0+1*2+3*4+5. The gerund m may extend cyclically. 
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u/  (Adverb)

INSERT (_)  u/y applies the dyad u between the items of y. Thus:
	  i.3 2	    +/i.3 2	     */2 3 4
0 1	      6 9			       24
2 3
4 5

If y has no items (that is, 0=#y), the result of u/y is the identity element of the verb u. An identity element of a function u is a value e such that either x u e is x, or e u x is x for every x in the domain (or perhaps some significant sub-domain such as boolean) of u. This definition of insertion over an argument having zero items extends partitioning identities of the form (+/y)–:(+/k{.y)+ +/k}.y to the cases k=. 0 and k=. #y.

The identity function of a verb u is a function ifu such that (ifu y)–:(u/y) if 0=#y. The identity functions are:

$&0&}.&$	      <  >  + – +. ~: |
$&1&}.&$     = <: >: * % *. %: ^ !
$&_&}.&$                <.
$&__&}.&$	              >.
i.&(0&,)&(2&}.)&$       ,
i.&(1&{.)&}.&$          @. {
=&i.&(1&{.)&}.&$        %. +/ . *
ifu&#                   u/
$&(v^:_1 ifu$0)&}.&$    u&.v

FUNCTION TABLE (_ _)  If x and y are numeric lists, then x */ y is their multiplication table. For example:

	  1 2 3 */ 4 5 6 7
 4  5  6  7
 8 10 12 14
12 15 18 21

In general, each cell of x is applied to the entire y. Thus x u/ y is x u"(lu,_) y.