@Adám can you provide a small explanation on the ⍤ operator (or link to one)?

@Uriel Have you looked at help.dyalog.com/16.0/Content/Language/Primitive%20Operators/…?

@Uriel Basically, f⍤k applies f on major arrays of rank k.

@Uriel Try it online!

@Adám awesome, thanks

@Uriel Also, you can use a two element k to specify the rank of of the desired left argument and right argument to each function call. You can also specify a 3-element k to allow ambivalent derived functions to have differing monadic rank and dyadic ranks. Finally, you can use negative k to specify (⍴⍴arg)-|k

@Adám I don't get the 3-element and negative k

@Uriel Negative rank

@Uriel Doesn't say much, does it? Try this!

Also, note that if k only has two elements, the rightmost one will be used when monadic.

now I'm afraid to go back to APL answers I've already done 😅

@Uriel Yeah, if you find you do things like (⊂A)f¨¨⊂⊂B then you need ⍤