What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? It is raining if and only if Sarah is a politician. David is curious if and only if Elisabeth is writing a letter. It is not raining. Elisabeth is not writing a letter.
It is not raining and Elisabeth is not writing a letter. Elisabeth is not writing a letter and it is not raining. If it rains, then Sarah is a politician. If David were curious, then Elisabeth is writing a letter. If Sarah were a politician, then it is raining. If Elisabeth writes a letter, then David is curious. Sarah is not a politician. David is not curious.