Problem: One char CAT

Code: One+char+CAT/tails_1644212990

Nibbles version: 0.2 | 0.21 | 0.22 | 0.23 | 0.24 | 0.25 | 1.00

Format: Compact | Simple | +Type | Table | JSON | .nbl (DeBruijn) | .nbl (names)

/ (foldr1) 
    @ (= fstLine) 
    (implicit arg = B) <--arg( B A )