Proving \neg x \vee x in Hilbert System: A Logical Dilemma

In summary, the conversation discusses using the Hilbert system to prove the logical expression \neg x \vee x. The speaker is unsure of which logical axioms to use and explains their attempts at a solution. Another person suggests that the expression is always true and questions the need to use the Hilbert system. The conversation ends with the mention of the Hilbert-Ackermann system and the speaker's interest in finding a proof using the Hilbert system.
  • #1
hamsterman
74
0

Homework Statement


Prove [itex]\neg x \vee x[/itex] using Hilbert system.

Homework Equations


The logical axioms. I'm not sure if I should state them, or whether there is a standard set. It seems to me that different sets are used. Anyway, the ones with disjunction in them are:
[itex]a \rightarrow a \vee b[/itex]
[itex](a \rightarrow c) \rightarrow ((b \rightarrow c) \rightarrow (a \vee b \rightarrow c))[/itex]

The Attempt at a Solution


If I wanted to use the first axiom, I'd have to prove x, which can be false. If I used the second axiom, I'd get what I wanted on the wrong side of the arrow. I don't think there is a way to reverse an arrow, except for [itex](x \rightarrow y) \rightarrow (\neg y \rightarrow \neg x)[/itex], but then I'd have no way to get rid of the negation. I'm lost. I'd appreciate help.
 
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  • #2
hamsterman said:

Homework Statement


Prove [itex]\neg x \vee x[/itex] using Hilbert system.

Homework Equations


The logical axioms. I'm not sure if I should state them, or whether there is a standard set. It seems to me that different sets are used. Anyway, the ones with disjunction in them are:
[itex]a \rightarrow a \vee b[/itex]
[itex](a \rightarrow c) \rightarrow ((b \rightarrow c) \rightarrow (a \vee b \rightarrow c))[/itex]

The Attempt at a Solution


If I wanted to use the first axiom, I'd have to prove x, which can be false. If I used the second axiom, I'd get what I wanted on the wrong side of the arrow. I don't think there is a way to reverse an arrow, except for [itex](x \rightarrow y) \rightarrow (\neg y \rightarrow \neg x)[/itex], but then I'd have no way to get rid of the negation. I'm lost. I'd appreciate help.

This seems like a lot of work to evaluate a very simple logical expression that is always true.
If x is true, then ~x is false, in which case ~x V x is true.
If x is false, then ~x is true, in which case ~x V x is again true.

How this fits into the Hilbert system, I have no idea, since that's a new one on me. I'm familar with Hilbert space, but not the Hilbert system.
 
  • #3
Mark44 said:
This seems like a lot of work to evaluate a very simple logical expression that is always true.
If x is true, then ~x is false, in which case ~x V x is true.
If x is false, then ~x is true, in which case ~x V x is again true.

How this fits into the Hilbert system, I have no idea, since that's a new one on me. I'm familar with Hilbert space, but not the Hilbert system.

There there is something called the Hilbert system, but it's actually called Hilbert–Ackermann system.
 
  • #4
I know it is true. That fact does not interest me. The proof using Hilbert system does.
 
  • #5
Can you list all of the axioms you are allowed to use? Like you said sometimes different sets are used, it'd be easier if we knew what ones you could use.
 

Related to Proving \neg x \vee x in Hilbert System: A Logical Dilemma

1. What is Hilbert logic axioms?

Hilbert logic axioms are a set of axioms or fundamental principles that were developed by German mathematician David Hilbert in the early 20th century. These axioms form the basis of a formal system for mathematical logic and are used to prove theorems in mathematics.

2. How are Hilbert logic axioms used?

Hilbert logic axioms are used as a starting point for mathematical proofs. They provide a set of rules that can be used to produce valid logical arguments, allowing mathematicians to prove the truth or falsity of mathematical statements.

3. What are the advantages of using Hilbert logic axioms?

Using Hilbert logic axioms allows for a more rigorous and systematic approach to mathematical proofs. It also allows for a clearer understanding of the logical structure of mathematical arguments and helps to avoid errors and inconsistencies.

4. Are Hilbert logic axioms the only way to prove mathematical theorems?

No, there are other systems of axioms and rules for mathematical logic, such as the Zermelo-Fraenkel set theory. However, Hilbert logic axioms are still widely used and have been influential in the development of mathematical logic.

5. Can Hilbert logic axioms be applied to fields other than mathematics?

Yes, Hilbert logic axioms can be applied to any field that requires logical reasoning, such as philosophy, computer science, and physics. However, the axioms may need to be modified or expanded to suit the specific needs of the field.

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