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6 questions with no upvoted or accepted answers
2 votes
0 answers
136 views

Circular Induction

Question: Suppose you have a circle with equal numbers of 0’s and 1’s on it’s boundary, there is some point I can start at such that if and travel clockwise around the boundary from that point, I will ...
user avatar
1 vote
0 answers
109 views

How to Complete this Proof about wffs in Propositional Logic?

For any wff $\mathfrak{F}$, define $\mathfrak{F}^*$ as the wff derived from $\mathfrak{F}$ by replacing all $\wedge$ with $\vee$ and all $\vee$ with $\wedge$. Claim: If all of the connectives of wff $...
Gary's user avatar
  • 515
1 vote
0 answers
442 views

Proof by induction, logic

I'd like you to comment if my following proof by induction is correct ($\mathbb{N} = \{0, 1, 2, \ldots\}).$ Thesis: Every formula constructed from variable $p$ and connectives $\land$, $\lor$, $\top$ ...
xorandiff's user avatar
  • 393
0 votes
1 answer
54 views

Prove Every Axiom Instance Has A Property

Consider an axiom form $\phi \rightarrow \phi$. I need to show that every instance of this has an even number of $\neg$'s. I'm not sure how to proceed. Here is what I've tried. I've assumed some ...
Rusty's user avatar
  • 255
0 votes
0 answers
493 views

Proof of Replaceability of Equivalent Formulas by Structural Induction

My class discussed the following theorem for which I wasn't able to make it to class. Its proof is supposed to involve structural induction but I am stuck in the inductive step... Let B |=| C. If A' ...
The_Questioner's user avatar
0 votes
1 answer
104 views

How to prove the that no formula can be represented in the form (F . G),

"No formula can be represented in the form (F . G), where F and G are formulas and is a binary connective, in more than one way. By representing a formula in the form ¬F or (F . G) we start “parsing”...
M.J.Watson's user avatar