I've been challenged on the university with this problem, which i can't resolve it. Can somebody help me? It needs to be resolved with propositional logic methods.
This is the problem:
Twelve University professors and students have been in the library at the time when a very expensive book
on propositional logic has disappeared. Each one entered once,stayed some time and left. If two of
them were in the library at the same time then at least one saw the other. Police interviewed these
students and professors and gathered the following evidence:
- Sem said that he saw Bryan and Zelda in the library.
- Caitlin swore that she saw George and Holly.
- Bryan said that he saw Sem and Vanessa.
- Maria claimed that she saw David and Vanessa.
- Nicolas said that he saw Alexander and Jana.
- David said that he saw Bryan and Zelda.
- Holly claimed that she saw Nicolas and Jana.
- Zelda testified that she saw Bryan and Maria.
- George said that he saw Alexander and Jana.
- Vanessa said that she saw Maria and Zelda.
- Alexander said that he saw George and Caitlin in the library.
- Jana said that she saw Holly and Caitlin.
Which one of the twelve University affiliates is not telling the truth? What he/she should have said
so that it doesn’t get caught?