10.8.2 d asks you to make a tableau of the following inference:
The solution in appendix J starts with this initial list:
Shouldn't it start with the negation of the initial formula? Or is this allowed by some black magic with the deduction theorem that I'm not aware of? I can see how it's similar to what the deduction theorem states, but I thought that was more part of the realm of semantics. Anyways, this initial list follows immediately from the negation of the inference so for the final answer it doesn't matter.
10.8.2 d asks you to make a tableau of the following inference:![image](https://user-images.githubusercontent.com/83274869/138604689-2ffdb067-bcd4-473a-8b39-9e5ee26d95bb.png)
The solution in appendix J starts with this initial list:
Shouldn't it start with the negation of the initial formula? Or is this allowed by some black magic with the deduction theorem that I'm not aware of? I can see how it's similar to what the deduction theorem states, but I thought that was more part of the realm of semantics. Anyways, this initial list follows immediately from the negation of the inference so for the final answer it doesn't matter.