How to translate a sentence with both a negate sufficient & negate necessary indicators in it?

hannahkay

How would you translate a sentence into lawgic that has both negate sufficient & negate necessary indicators in it?

Ex: "No entry after 9 pm without a valid ID." or "One cannot bake a cake without flour."

letslearntogether

No entry after 9 pm without a valid ID: entry after 9 PM ---> valid ID

One cannot bake a cake without flour: can bake a cake ---> flour

Essentially what I recommend is that you negate the first statement and keep the next part the same. We know that if you are allowed entry after 9 PM you have a valid ID; we know that if you can bake a cake you have flour. The second half is the exception to a rule and is thus the necessary condition.