I am writing about objects A and B. They rely on well-known object C. I have defined A and B to be equal but I can use C to show that they are not equal. My intention is to show that C cannot be as commonly defined. Here is my question:
Is it allowed in the math grammar to use a theorem to deliberately prove something that is untrue? I have one theorem that shows A(C)=1 and I can make another that shows B(C)=5. This is wrong because A(C)=B(C). Therefore, it feels wrong to make a theorem that proves B(C)=5. My intention is to derive the result B(C)=5 so that later I can show that there is a problem with C. What technique can I use to show something provisionally with the intention to show that actually it is wrong? I feel like it would be ugly to use a theorem to "prove" something and then say, "Haha, actually that theorem was a lie!!!" How is this sort of thing done? THANKS