In my opinion, this play has a few themes. The first theme: Do not underestimate people. Hal and Claire did not believe Catherine when she said she wrote the "Proof" because she did not have a college degree. Since the handwriting looked like Robert's writing, they thought he had written it. Catherine was underestimated. Hal and Claire neglected to look at the fact that Catherine had the same math ability as her Dad, Robert. She …showed first 75 words of 384 total…

…showed last 75 words of 384 total…that her "Proof" does not flow as smoothly as her father's work did. It was almost as if she was trying to take the attention away from her own work. Second, she gives Hal the key to the drawer where she keeps the "Proof" she wrote. I think she does this hoping that he will publish and take credit for it. Saying and doing what she did makes me believe that she enjoys her anonymity.