What's that Language?

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Across
  1. 2. Commutativelaws
  2. 6. contrapositive
  3. 7. simplification
  4. 8. Contradiction
  5. 10. conjunction
  6. 11. Idempotentlaws
  7. 12. implications
Down
  1. 1. Biconditional
  2. 3. modustollens
  3. 4. propositionalcaluculus
  4. 5. Identitylaws
  5. 9. Distributivelaws
  6. 13. inverse