Consider the following premises. John is playing squash or it is not snowing. John is playing squash if and only if Elisabeth is an artist. Elisabeth is an artist or it is snowing. Can we infer the following from them? John is not playing squash.
 From the fact that John is playing squash or it is not snowing we can infer that if it snows, then John is playing squash. From the fact that John is playing squash if and only if Elisabeth is an artist we can infer that if Elisabeth were an artist, then John is playing squash. Finally, from the fact that if Elisabeth were an artist, then John is playing squash, that if it snows, then John is playing squash, and that Elisabeth is an artist or it is snowing we can infer that John is playing squash, which contradicts that John is not playing squash. Therefore, the answer is no.