Category "negation"

z3py: How to convert a formula into NNF format?

I wanted to convert a formula to its NNF format using z3py. For e.g., Given Or(Not(And(i1, Not(And(i0, i4, i1, i2)))), And(i3, i1, i2)) I want Or(Not(i1), And(

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)

Repeated negation (!) operators in bash do not negate each other

So this is more an oddity I've come up against than something I really want to use. But I found something I didn't understand with the bash extended test syntax