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**Show that the following derivability claim holds in SD.**

(I'll use ">" to stand in for conditional.)

(I'll use ">" to stand in for conditional.)

Code:

`{(A > F) & (F > D), ((M v H) v C) > A, ~(M v H) & C} entails D`

I'm only allowed to use the basic derivation rules of SD:

Reiteration (R)

Conjunction Intro. (&I) and Conjunction Elim. (&E)

Conditional Intro. (>I) and Conditional Elim. (>E)

Negation Intro. (~I) and Negation Elim. (~E)

Disjunction Intro. (vI) and Disjunction Elim. (vE)

Biconditional Intro. (triplebarI) and Biconditional Elim. (triplerbarE)

I've made numerous attempts at this problem, while growing more and more frustrated after each failure.

Here is what I believe to be my closest answer:

Code:

```
1. (A > F) & (F > D) [assumption]
2. ((M v H) v C) > A [assumption]
3. ~(M v H) & C [assumption]
4. M v H [?????]
5. C [3 &E]
6. (M v H) v C [5 vI]
7. A > F [1 &E]
8. A [2,5 >E]
9. F > D [1 &E]
10. F [7,8 >E]
11. D [9,10 >E]
```

Thank you - any help would be greatly appreciated.