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user131753
1:04 PM
@user21820:
 
user131753
Just a short question related to the Deduction Theorem. Is the Deduction Theorem for Hilbert-style system of First Order Predicate Calculus a meta theorem or a meta-meta-theorem? — user 170039 9 hours ago
 
user131753
The Deduction Theorem is usually referred to as a meta theorem. But I am wondering because the statement of the theorem (at least the one with which I am familiar) is, "If $\Delta$ be a set of formulas and $\Delta \cup \{P\}\vdash Q$ then $\Delta\vdash P\to Q$ where $P,Q$ are also another formulas."
 
user131753
If it is a meta theorem then what is the meta language of the Hilbert-style system of First Order Predicate Calculus @user21820 with respect to which it is a meta theorem?
 
user21820
user21820
@user170039 Much as I would like to help anyone in logic, as I said earlier I will not help you as long as you insist on supporting cranks who incite violence. Note that he even now says on his profile that his meta post got censored, when you are the one who pestered the moderators incessantly until they delete it.
 
 
1 hour later…
user21820
user21820
2:19 PM
 
 
2 hours later…
BeginningMath
BeginningMath
3:53 PM
i really would appreciate if someone could help me so i knew how to prove such basic things using the deduction theorem
 
user21820
user21820
4:19 PM
@BeginningMath Did you try using the Fitch-style system I linked you to? For pure first-order logic, the system itself more or less tells you how the proof must go.
 
user21820
user21820
4:54 PM
Post your attempts here and I'll check and comment on them. You really have to understand at least one Fitch-style system before you can fully understand any other deductive systems.
 

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