Category "proof"

LSH - proof of the probabilities of success and expected collisions

Hi, I'm at a loss trying to solve this excersie. I'd really appreciate some help! Thank you. Definition: A family of hash functions H = {h : X → U} is (r1,

Proving A → ¬ (¬ A ∧ B) in Lean

I am having a hard time proving A → ¬ (¬ A ∧ B) with the Lean theorem prover. I set it up like this: example : A → ¬ (¬ A ∧ B)