# Generating false statements in propositional calculus?

Contents

## What makes the proposition false?

This kind of sentences are called propositions. If a proposition is true, then we say it has a truth value of “true”; if a proposition is false, its truth value is “false”. For example, “Grass is green”, and “2 + 5 = 5” are propositions. The first proposition has the truth value of “true” and the second “false”.

## What propositional logic which statement is false?

A proposition formula which is always false is called Contradiction. A proposition formula which has both true and false values is called. Statements which are questions, commands, or opinions are not propositions such as “Where is Rohini”, “How are you”, “What is your name”, are not propositions.

## Which is false statement about value proposition?

If our original proposition is false, then its negation is true. If our original proposition is true, then its negation is false.

Truth Value.

p NOT p
F T

## How do you prove a proposition is false?

In general, to prove a proposition p by contradiction, we assume that p is false, and use the method of direct proof to derive a logically impossible conclusion. Essentially, we prove a statement of the form ¬p ⇒ q, where q is never true. Since q cannot be true, we also cannot have ¬p is true, since ¬p ⇒ q.

## How do you determine the truth value of a proposition?

Calculating the Truth Value of a Compound Proposition

1. For a conjunction to be true, both conjuncts must be true.
2. For a disjunction to be true, at least one disjunct must be true.
3. A conditional is true except when the antecedent is true and the consequent false.

## Is the assertion This statement is false a proposition?

It isn’t saying anything about anything at all! But all propositions are declarative statements and “This statement is false”, doesn’t say anything whatsoever. Therefore you can rest assure that “This statement is false”, is not a proposition.

## What is an example of a propositional statement?

For example, in terms of propositional logic, the claims, “if the moon is made of cheese then basketballs are round,” and “if spiders have eight legs then Sam walks with a limp” are exactly the same. They are both implications: statements of the form, P→Q. P → Q .

## What is the truth value of true or false?

In this way, the conjunction itself has its own truth value which is distinct from each of the conditions contained within (ie one of the conditions may be true, but the value of the conjunction is false).

AND truth table.

P Q P AND Q
FALSE TRUE FALSE
FALSE FALSE FALSE

## Do propositions have truth values?

The term ‘proposition’ has a broad use in contemporary philosophy. It is used to refer to some or all of the following: the primary bearers of truth-value, the objects of belief and other “propositional attitudes” (i.e., what is believed, doubted, etc.), the referents of that-clauses, and the meanings of sentences.

## How do you tell if a compound statement is true or false?

The only way that a disjunction can be false is if both parts are false in our case we have the first part is true and the second part is false. So the whole statement must be true.

## How do you determine if a compound statement is true or false?

Disjunction

1. Disjunction statements are compound statements made up of two or more statements and are true when one of the component propositions is true. …
2. In logic, we use inclusive or statements.
3. The p or q proposition is only false if both component propositions p and q are false.

## What are the truth values for ~( p ∨ Q?

So because we don’t have statements on either side of the “and” symbol that are both true, the statment ~p∧q is false. So ~p∧q=F. Now that we know the truth value of everything in the parintheses (~p∧q), we can join this statement with ∨p to give us the final statement (~p∧q)∨p.

Truth Tables.

p q p∨q
F T T
F F F

## What is the negation of P ∨ Q ∧ P ∧ Q )?

The negation of p ∧ q asserts “it is not the case that p and q are both true”. Thus, ¬(p ∧ q) is true exactly when one or both of p and q is false, that is, when ¬p ∨ ¬q is true. Similarly, ¬(p ∨ q) can be seen to the same as ¬p ∧ ¬q.

## What is the converse of P → Q?

The converse of p → q is q → p. The inverse of p → q is ∼ p →∼ q. A conditional statement and its converse are NOT logically equivalent. A conditional statement and its inverse are NOT logically equivalent.

## Are the statements P ∧ Q ∨ R and P ∧ Q ∨ R logically equivalent?

Since columns corresponding to p∨(q∧r) and (p∨q)∧(p∨r) match, the propositions are logically equivalent. This particular equivalence is known as the Distributive Law.

## Which of the proposition is p ∧ (~ p ∨ q is?

The proposition p∧(∼p∨q) is: a tautology. logically equivalent to p∧q.

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## Is {[( P ∧ Q → R → P → Q → R )]} tautology?

Thus, `[(p to q) ^^(q to r) ] to ( p to r)` is a tautolgy. Step by step solution by experts to help you in doubt clearance & scoring excellent marks in exams.

## Are these statement are equivalent P ∨ Q and Q ∧ P?

Theorem 2.6. For statements P and Q, The conditional statement P→Q is logically equivalent to ⌝P∨Q. The statement ⌝(P→Q) is logically equivalent to P∧⌝Q.

## Is a statement which is always false?

Contradiction: A statement form which is always false.

## Which of the following propositions is tautology Pvq → Qpv Q → P PV P → Q Both B & C?

The correct answer is option (d.) Both (b) & (c). Explanation: (p v q)→q and p v (p→q) propositions is tautology.

## Can two false sentences be logically equivalent?

No two false sentences are logically equivalent. circumstances. A pair of equivalent sentences must both be false at the same time if they are false at all.

## What is logically false?

Definition: a sentence is logically false if and only if it is not possible for it to be true. Although the sentence ‘Al Gore is the President’ is false, it could have been true had circumstances been different. However some sentences had to be false. Such a sentence is logically false.

## What is a necessary falsehood?

A necessary falsehood is a proposition false in all possible worlds. A contingent truth is a proposition true (in the actual world), but false in at least one possible world. A contingent falsehood is a proposition false in the actual world, but true in at least one possible world.