Hi i'm just attempting a question on sets and maps but i'm a little confused by my lecturers notation and was hoping someone could help.
Ive got the sets X, Y and Z. π is the mapping of X to Y and ψ is the mapping Y to Z and then the composite π ∘ ψ is the mapping X to Z. But here is were I get stuck, it says the composite π ∘ ψ is the map " i^(πψ) := (i^π)^ψ for all i ∈ X " and i've genuinely no idea what this means.
The question is then "Give an example for πψ = πψ* but ψ ≠ ψ*." I'm not exactly sure what the question is asking for.