Webpage for Mathematical Logic

Important Question Types:

  1. Checking validity of First Order Logic Statements
  2. Checking validity of Propositional Logic

Recent questions tagged mathematical-logic

2 2 votes
1 1 answer
306
306 views
Which of the following is/are logically equivalent to $\neg(P \Longrightarrow Q)?$$\neg P \vee Q$$\neg P \wedge Q$$Q \Longrightarrow P$$P \wedge \neg Q$
6 6 votes
2 2 answers
550
550 views
Which of the following best expresses the statement "Nobody loves everybody" in predicate logic?$\neg \exists x \forall y L(x, y)$$\neg \forall x \exists y L(x, y)$$\fora...
1 1 vote
1 1 answer
414
414 views
Which of the following represents the statement "There is exactly one person whom everybody loves"?$\exists x \forall y L(y, x)$$\exists x[\forall y L(y, x) \wedge \foral...
4 4 votes
2 2 answers
416
416 views
Which of the following expressions is a tautology?$(P \rightarrow Q) \vee(Q \rightarrow P)$ $(P \vee Q) \rightarrow(P \rightarrow Q)$ $((P \rightarrow Q) \wedge P) \right...
2 2 votes
4 4 answers
584
584 views
Statement: A sufficient condition for the warranty to be good is that you bought the computer less than a year ago.Let:P: You bought the computer less than a year ago.Q: ...
2 2 votes
4 4 answers
749
749 views
Statement: It is necessary to wash the boss's car to get promoted.Let:P: You wash the boss's car.Q: You get promoted.Which of the following propositional formulas express...
1 1 vote
1 1 answer
355
355 views
Let $\varphi$ be a propositional formula on $n$ variables, with $n \geq 1$. Consider the following statements.$\varphi$ is satisfiable$\neg \varphi$ is unsatisfiable$\var...
3 3 votes
5 5 answers
892
892 views
Three boxes are presented to you. One contains gold, the other two are empty. Each box has imprinted on it a clue as to its contents; the clues areI. (Box 1) The gold is ...
1 1 vote
1 1 answer
419
419 views
Let $\mathbf{T}(\mathbf{x}, \mathbf{y})$ be the predicate " $\mathbf{x}$ is taller than $\mathbf{y}$ ", where $\mathbf{x}, \mathbf{y} \in$ People. Consider the logical ex...
3 3 votes
4 4 answers
590
590 views
Which of the inferences are valid given the premises?$\begin{array}{l}\text{} (I_{1})\text{}\end{array} \quad \begin{array}{l}\text{All birds have feathers.} \\\text{Robi...
6 6 votes
7 7 answers
879
879 views
Consider the statement form $p \Rightarrow q$ where $p=$ "If Tom is Jane's father then Jane is Bill's niece" and $q=$ "Bill is Tom's brother." Which of the following stat...
1 1 vote
5 5 answers
571
571 views
Q4. The statement form $(p \Leftrightarrow r) \Rightarrow(q \Leftrightarrow r)$ is logically equivalent to:$(\sim p \vee r) \wedge(\sim r \vee p) \Rightarrow(\sim q \vee ...
1 1 vote
6 6 answers
656
656 views
Which of the following statements are tautologies?(You may select more than one option.)$(p \wedge q) \rightarrow p$$p \rightarrow(p \vee q)$$p \rightarrow(p \rightarrow ...
5 5 votes
6 6 answers
631
631 views
2 2 votes
7 7 answers
766
766 views
Mark all the statements that are logically true:If $1+1=2$, then $2+2=5$If $1+1=2$, then $2+2=4$If $1+1=3$, then $2+2=5$If monkeys can fly, then $1+1=3$
0 0 votes
2 answers 2 answers
459
459 views
"For any natural number n, n is even if and only if n^2 is even" in first order logicdomain : set of real numbers∀n[Nat(n)→(Even(n)↔Even(n^2))], correct answer ∀n[Nat(n)...