| Decrement | <: 0 0 0 | Less than or Equal | 
| <:y is y-1 . For example: <: 2 3 5 7 1 2 4 6Also see Not (-.) . | x<:y is 1 if x is less than or 
equal to y , and is otherwise 0 .   
See Equal (=) for a discussion 
of tolerance. The fit conjunction (!.) applies 
to <: . | 
   n=: 5
   <: ^: _1 n
6
        
   <:^: 0 1 2 n               NB. Here ^: applies to a noun right argument (0 1 2)
5 4 3
   <: ^: i. n                 NB. Here ^: applies to a verb right argument (i.)
5 4 3 2 1
   */ <: ^: i. n
120
            
   f=: */ @ (<: ^: i.)
   f n
120
            
   f"0 i. n
1 1 2 6 24
   (f"0 = !) i. n
1 1 1 1 1
  
   <:/ ~ i. 5                 NB. Table of the dyad <:
1 1 1 1 1
0 1 1 1 1
0 0 1 1 1
0 0 0 1 1
0 0 0 0 1