Which of the following is equivalent to the semi-join expression: s ⋉ r?
a. r ⋊ s b. r ⋉ s
c. both a. and b. d. neither a. nor b.

Convert and simplify the following sentences to conjunctive normal form (cnf): (a) (p → (q → r)) → (p → (r → q)) (b) (p ∧ q) → (¬p ↔ q) (c) ((p → q) ∧ ¬q) → ¬p

State the parts of a variable declaration?

Helen's credit card has an apr of 15.32% and a grace period of 17 days and helen pays her balance in the full every month. if her last billing cycle ended on september 26, 2009, and she made her payment on october 11, 2009, did she owe any interest on her last statement's balance?