| d0=: -:&(/:~) | Are x and y permutations of each other? |
| m1=: /:~-:i.@# | Is y a permutation vector? |
| m2=: -:-@|: | Is y antisymmetric? |
| m3=: -:|: | Is y symmetric? |
| m4=: [:+./[:*./]=/0 1"_ | Are all atoms of Boolean list y equal? |
| m5=: *./ .= +./ | Are all atoms of Boolean list y equal? |
| m6=: *./ .= *./ | Are all atoms of Boolean list y equal? |
| d7=: -.@(] <:/ .>: >.@] , [)"1 | Is y in the half open on the right interval x and is it an integer? |
| d8=: e. | Is list x a row of array y? |
| m9=: *./@(= >./\) | Are columns of y in ascending order? |
| m10=: *./@(= <./\) | Are columns of y in descending order? |
| m11=: >./=<./ | Are atoms of numerical list y equal? |
| m12=: *./ +. -.@(+./) | Are atoms of Boolean list y equal? |
| m13=: *./ = +./ | Are atoms of Boolean list y equal? |
| m14=: *./@(= {.) | Are atoms of list y equal? |
| m15=: 0:=#|+/ | Are atoms of Boolean list y equal? |
| m16=: *./@(#1&|.) | Are atoms of Boolean list y equal? |
| m17=: ([:,:0:,#)-: v19"_ rxmatch ] | Is y a legal J name? |
| d18=: rxmatch=: 17!:0 | '' to get rxmatch |
| v19=: '[[:alpha:]][[:alnum:]_]* '"_ | 'regex' to get alpha: and alnum: |