You can find them on the Grades page – send me an email if you don’t remember the password.
Regards,
Prof. Reitz
Logic on Math StackExchange
- What is the justification for the RAA rule, and how does it relate to the Principle of Explosion? (Mathematical Logic by Chiswell and Hodges) September 24, 2023I am reading through Mathematical Logic by Ian Chiswell and Wilfrid Hodges and am trying trying to finalize my understanding of the RAA rule introduced in section 2.6. The book states the rule in the following way: Suppose we have a derivation whose conclusion is $\bot$. Then there is a derivation $$\require{cancel}(\cancel{~\lnot\phi~}) \\\\\ D \\\\\ […]Artyom Elessar
- Universal generalization and the Deduction theorem September 24, 2023Universal generalization The rule of universal generalization in FOL is stated as follows: (Gen) From $p$ we may infer $(\forall x)p$ provided $x$ does not occur free in any premiss which has been used in the proof of $p$. I don't understand what this means, particularly for deduction sequences. Given a set of formulae $S$ […]Hernán Ibarra Mejia
- Gödel Incompleteness Theorems Proof September 23, 2023Is the proof outline of Godel’s Incompleteness Theorems on Simple Wikipedia correct?Caleb
- Tautological statements September 23, 2023I have been tasked with finding how many of the following statements are tautologies, and was wondering which method would be the best to solve this assignment fast. My teacher said I should use no more than 5 minutes on it. How can I quickly spot which of these statements are tautologies?Marcus K. Johnson
- Can Someone prove the following: (A+B)(B'+C)(A+C) = (A+B)(B'+C) In Context of Digital Logics? September 23, 2023I am unable to prove this using any types of Standard expansion, it would be appreciable if someone used the Basic Laws such as Commutative Law, Absorption Law etc.Dan Forester
- How to prove $\phi \models \psi$ iff $\phi \cup \{\neg \psi\}$? September 22, 2023I want to prove $\phi \models \psi$ iff $\phi \cup \{\neg \psi\}$ unsatisfiable. What's the meaning of the union operator w.r.t. satisfiability in FOL? Does it mean that all such interpretations $\mathcal{I}$ of the LHS also have to model $\phi$ and $\{\neg \psi\}$? So $\phi \cup \{\neg \psi\} \Leftrightarrow \phi \wedge \neg \psi$ ? I […]Martin Stuwe
- Statement with conjunctions and disjunctions [closed] September 22, 2023Is it correct to say $$ (~a \&\& ~ b) \mid\mid ( ~a \&\& b \&\& c) = ( ~a \&\& ~b) \mid\mid ( ~a \&\& c), $$ where $\&\&$ means "conjunction" and $\mid\mid$ means "disjuncton". I am also not sure whether I can simplify it further, so please explain if that is possible and […]Nadia
- How can one claim they proved $φ$ or $¬φ$ without knowing which? September 22, 2023I've been told True Arithmetic is syntactically complete(either $φ$ or $¬φ$ is provable for every $φ$), yet one cannot decide which of the two. This makes no sense to me. How can one say they proved either $φ $ or $¬φ$, without knowing which?setblack7
- Cardinality in an instance where evolution describes everything? [closed] September 22, 2023The simplest algorithm to represent evolution I can think of (as a physics student) is this: Given a system with probability outcomes $p_1$ and $1-p_1$. Life will search if $p_1 > 1- p_1$ or $1-p_1 > p_1$. There are 2 values over here required such as certainty of accuracy of $p_1$ and judgement of $p_1 […]More Anonymous
- Finding the relationship (equivalence or implication) between two expressions September 22, 2023I am trying to find the relationship between $$\exists X \; (p(X) ∧ q(X))$$ and $$\exists X \; p(X) ∧ \forall X \; q(X).$$ I believe that quantifiers cannot be used in forming truth tables, after all both expressions become equal if we take out the quantifiers. Without a truth table I do not know […]Govt_employee
Leave a Reply