I am trying to prove the following using natural deduction and this is what I have so far. I am not sure, however, if this is entirely correct.
If I could get some verification and be pointed to the right direction, that would be great.
a ∧ ¬a |- b ∧ ¬b
1 a ∧ ¬a assump 0
2 b |- a ∧ ¬a
2.1 b assump 2
2.2 ¬b ¬I 2.1
3 b ∧ ¬b ∧I 2.1, 2.2
4 ¬b |- a ∧ ¬a
4.1 ¬b assump 4
4.2 b ¬E 4.1
5 b ∧ ¬b ∧I 4.1, 4.2
This is not a duplicate as the symbols and solutions provided with the question it being marked against are different.