Fitch Notation Subderivations and Sequents I am using Fitch Notation and am curious how you would write this one subderivation with just syntactic consequences (⊢)? Any help would be greatly appreciated. I was thinking you could maybe write it like this $(A, B, (C\vdash B))\vdash (C\rightarrow B)$, but I am still unsure.

I'm reading your symbolism as follows:

> "if $A,B,C ⊢ B$, then $A,B ⊢ C→B$.

If correct, this is an application of the rule ($\to$-I) of Natural Deduction that formalize the inference:

> if we have a derivation of $B$ from assumptions $A,B$ and $C$, we can produce a new derivation of $C \to B$ from assumptions $A$ and $B$.