# Logical notation

The way in which logical concepts and their interpretations are expressed in natural languages is often very complicated. In order to reach an overview of logical truthslogical truthsBroadly speaking, a logical truth is a statement which is true regardless of the truth or falsity of its constituent propositions. In other words, a logical truth is a statement which is not only true, but one which is true under all interpretations of its logical components (other than its logical constants).

## What is an example of a logical statement?

Anything that lets us infer a new fact about something mathematical from given information is a logical statement. For example, “The diagonals of a rectangle have the same length” is a logical statement. The hypothesis is the part that can help us if we know it’s true. When could this statement be useful?

## What does this symbol ↔ represent?

Logic math symbols table

Symbol Symbol Name Meaning / definition
equivalent if and only if (iff)
for all
there exists
there does not exists

## What does ∨ mean in logic?

inclusive disjunction

The symbol ” ∨ ” signifies inclusive disjunction: a ∨ statement is true whenever either (or both) of its component statements is true; it is false only when both of them are false. (See the truth-table at right.)

## What are the symbols used in logic?

Basic logic symbols

Symbol Unicode value (hexadecimal) Logic Name
⇒ → ⊃ U+21D2 U+2192 U+2283 material implication
⇔ ≡ ↔ U+21D4 U+2261 U+2194 material equivalence
¬ ˜ ! U+00AC U+02DC U+0021 negation
U+1D53B Domain of discourse

## What are the 4 types of logic?

There are four basic forms of logic: deductive, inductive, abductive and metaphoric inference.

## What does P ↔ Q mean?

The biconditional or double implication p ↔ q (read: p if and only if q) is the statement which asserts that p and q if p is true, then q is true, and if q is true then p is true. Put differently, p ↔ q asserts that p and q have the same truth value.

## What does |= mean in logic?

They described it as : In logics, meaning is often described by a satisfaction relation. M |= A. that describes when a situation M satisfies a formula A. So, I also searched some examples.

## What does ⋅ mean?

× multiplication sign

The ⋅ is the same as the × multiplication sign, but it is often used in mathematical notations to prevent possible confusion with the letter ‘x’. e.g. y × x is often written as y ⋅ x. ÷ Division, divide. This is used to indicate that one number is divided by another, e.g. 3 ÷ 2 = 1.5.

## What does +- mean in math?

plus/minus sign

Definition of plus/minus sign

: the sign ± used to indicate a quantity (such as 2 in “the square root of 4 is ±2”) taking on both an algebraically positive value and its negative and to indicate a plus or minus quantity (such as 4 in “the population age was 30 ± 4 years”) — called also plus/minus symbol.

## What is this symbol called?

This table contains special characters.

Symbol Name of the symbol Similar glyphs or concepts
‘ ‘ Apostrophe Quotation mark, Guillemet, Prime, Grave
* Asterisk Asterism, Dagger
Asterism Dinkus, Therefore sign
@ At sign

## What is [email protected] symbol called?

Officially, this symbol is called commercial at. Unofficially, most people seem to refer to it as the at sign or just at. Recently, there has also been a movement to call it the atmark. There are also numerous nicknames for it, including snail, curl, strudel, whorl, and whirlpool.

## What is the * symbol called?

In English, the symbol * is generally called asterisk. Depending on the context, the asterisk symbol has different meanings. In Math, for instance, the asterisk symbol is used for multiplication of two numbers, let’s say 4 * 5; in this case, the asterisk is voiced ‘times,’ making it “4 times 5”.