The left identity of a binary operator ⋄ is a value iℓ such that, for any x, the expressions x and iℓ ⋄ x are equivalent. The right identity of ⋄ is a value ir such that, for any x, the expressions x...

The left identity of a binary operator ⋄ is a value iℓ such that, for any x, the expressions x and iℓ ⋄ x are equivalent. The right identity of ⋄ is a value ir such that, for any x, the expressions x and x ⋄ ir are equivalent. (Again, some operators may not have left or right identities.) What are the left and right identities of ⇒ (if they exist)?