Circle Diaeresis is a Dyadic operator with an ambivalent left operand
Operator Circle Diaeresis means
-⍥⌊ 3.6 ⍝ Same as ∘ or ⍤ monadically
¯3
5.1 -⍥⌊ 3.6 ⍝ Applies ⌊ to both arguments
2
'Dyalog' ≡⍥⎕C 'DYALOG' ⍝ Case-insensitive match
1
'Dyalog' ≡⍥⎕C 'IBM'
0