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
2 2 answers
516
516 views
Given the following where $p, q, r, s, t$ are statement variables:(i) $(\sim r \rightarrow \sim r) \vee(\sim q \rightarrow q) \vee(t \rightarrow \sim t)$(ii) $(p \wedge q...
0 0 votes
1 1 answer
562
562 views
Assume the domain is $\mathbb{R}$. Which of the following statements are true?$\forall x \exists y(x y=1)$$\exists x \forall y\left(x^{2} \geq y^{2}\right)$$\exists x \fo...
0 0 votes
1 1 answer
381
381 views
Let $S$ be the set of students and $x \in S$. We define the following predicates:$\operatorname{SoC}(x): x$ is a computing student;$\operatorname{CS} 1231(x): x$ has take...
1 1 vote
1 1 answer
540
540 views
Which of the following statements are true?$\sim(p \rightarrow q) \equiv(p \vee(p \rightarrow \sim q))$$(p \rightarrow(q \vee r)) \leftrightarrow((p \wedge \sim q) \right...
0 0 votes
1 1 answer
216
216 views
Does there exist a polynomial $q(x)$ with integer coefficients such that $q(1)=2$ and $q(3)=5$ ? Given an example if there is one. Justify, if there is not.
0 0 votes
2 2 answers
346
346 views
Which of the following statements is/are true for real numbers $x, y$ ?If $x^{2}=y^{2}$ then $x=y$.If $x^{3}=y^{3}$ then $x=y$.If $x < y$ then $x^{2}<y^{2}$If $x < y$ the...
0 0 votes
0 0 answers
146
146 views
Let $f$ be a continuous real-valued function on $[0,1]$ such that\[\int_{0}^{1} f(x) d x=\int_{0}^{1} x f(x) d x=0 .\]Pick the correct statement(s) from below.$f$ must ha...
0 0 votes
0 0 answers
266
266 views
Consider a city with $n$ East-West Streets (EWS) and $n$ North-South Avenues (NSA). The EWS are the line segments $\{y=j \mid 1 \leq x \leq n\}$ for all $j \in\{1,2, \ldo...
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0 0 answers
115
115 views
Let $f$ be a single variable, real valued function such that all its derivatives exist. We say that $f$ changes sign at some point $x_{0}$ in the domain if the product $f...
0 0 votes
0 0 answers
160
160 views
Solitaire Tic-Tac-Toe is a new game on the market. Instead of adding X's and O's to an empty $3 \times 3$ grid, you start with a $3 \times 3$ grid in which every position...
0 0 votes
0 0 answers
126
126 views
Which of the following statement(s) is/ are true?$(2023!)^{2}<(2023)^{2023}$.$2^{\sqrt{7}}>2^{\frac{21}{8}}$.$e^{\frac{1}{e}}<\sqrt{2}$.$\log _{10} 7<\frac{1+\log _{10} 5...
0 0 votes
0 0 answers
122
122 views
Let $n \geq 2$ be an integer. Let $V$ be the $\mathbb{R}$-vector-space of homogeneous real polynomials in three variables $X, Y, Z$ of degree $n$. Let $p=(1,0,0)$. Let\[W...
0 0 votes
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121
121 views
Let $X$ be a compact topological space. Let $f: X \longrightarrow \mathbb{R}$ be a function satisfying $f^{-1}([n, \infty))$ is closed for all $n \in \mathbb{N}$. Pick th...
0 0 votes
0 0 answers
146
146 views
Let $f:[0,1] \longrightarrow \mathbb{R}$ be a continuous function and $E \subseteq[0,1]$. Which of the following are true?If $E$ is closed, then $f(E)$ is closed.If $E$ i...
0 0 votes
0 0 answers
163
163 views
Let $A$ be the ring of all entire functions under point-wise addition and multiplication. Then which of the following are true?$A$ does not have non-zero nilpotent elemen...
0 0 votes
1 1 answer
235
235 views
A non-empty collection $\mathcal{S}$ of subsets of a set $U$ is a scattering of $U$ if it satisfies the following condition: for all $A, B \i...
0 0 votes
1 1 answer
208
208 views
We assume that all the arguments are non-negative integers. The operation x div $2$ divides x by $2$ and returns an integer, discarding the fractional part.int f(int x, i...
1 1 vote
2 answers 2 answers
421
421 views
Lets say we have a sentence, "If it rains, then I will take the cab". In this if it actually rains and the person takes the cab, then we say implication holds and resulta...
0 0 votes
1 1 answer
483
483 views
((¬p∧q)∧(q→(p→r)))→¬rIs it tautology?
0 0 votes
0 0 answers
290
290 views
Let P(x) and Q(x) be arbitrary predicates. Which of the following statements is always TRUE?(a) (Vx(P(x) vQ(x))) ((VP(x)) (V1Q(x)))(b) (x(P(x)Q(x))) ((VIP(x))(Q(x)))(c) (...
0 0 votes
1 1 answer
188
188 views
For a polynomial of the form $a_{0}+a_{1} x+\cdots+a_{m} x^{m}$ having degree $m>1$, it is known that the coefficients satisfy the relation $\frac{a_{i-1}}{a_{i-1}+a_{i}}...
0 0 votes
0 0 answers
281
281 views
For any undirected connected graph $G$, let $\chi(G)$ be the minimum number of colours needed to colour all the vertices of $G$ in such a way that no two adjacent vertice...
0 0 votes
1 1 answer
440
440 views
What is the meaning of NOT Valid in logic?Does "Not Valid" means Invalid only, Or NOT-Valid can have two possibilities, it can be either INVALID or Satisfiable.As per my ...