 # Mathematical Logic

Logic in simple words means to reason. This reasoning can be a legal opinion or even a mathematical confirmation. Well, you can apply certain logic in Mathematics as well and solve mathematical logic problems. Some of the basic mathematical logical operators that you can use in your day to day life are conjunction, disjunction, and negation. You denote these mathematical logic symbols as, ^ for representing conjunction, v for representing disjunction, and for representing negation. In this article, let us discuss some of the basic mathematical logic, mathematical logic formulas along with the truth table and some math logic examples with answers.

### Classification Of Mathematical Logic

The mathematical logic can be subdivided into four different fields which are as follows:

1. Set Theory

2. Recursion Theory

3. Model Theory

4. Proof Theory

### Mathematical Logical Operators

There are three basic mathematical logical operators that you use in mathematics. These are:

1. Conjunction or (AND)

2. Disjunction or (OR)

3. Negation or (NOT)

Now, let us take a look at all these mathematical logical operators in detail.

### Mathematical Logic Formulas

Conjunction or (AND)

You can easily join two mathematical logic statements by using the AND operand. It is also called as a conjunction. You can represent it in the symbol form as ∧. In this operator, if either of the statements is false, then the result is false. If both the statements are true, then the result is true. The inputs can be two or more, but the output you get is just one.

## Truth Table Of The Conjunction (AND) Operator

 Input A Input B Output A AND B (A ∧ B) True True True True False False False True False False False False

### Disjunction or (OR)

You can join two statements easily with the help of the OR operand. It is also called as disjunction. You can represent it in the symbolic form as ∨. In this operator, if either of the statements is true, then the result you get is true. If both the statements are false, then the result is false. It consists of two or more inputs but only one output.

## Truth Table Of The Disjunction (OR) Operator

 Input A Input B Output A OR B (A V B) True True True True False True False True True False False False

### Negation or (NOT)

Negation is an operator that gives the opposite statement of the statement which is given. It is also called as NOT and is denoted by ∼. It is an operation which would give the opposite result. When the input is true, the output you get is false. When the input is false, the output you get is true. It consists of one input and one output.

## Truth Table Of The Negation (NOT)

 Input Output A Negation A (∼ A) True False False True

### Mathematical Logics Problems

Now that you know about the mathematical logic formulas, let us take a look at math logic examples with answers.

Example 1:

Construct a truth table for the values of conjunction for the following given statements:

r: x is an odd number

s: x is a prime number

Solution:

Given:

r: x is an odd number

s: x is a prime number

Since each statement given represents an open sentence, the truth value of r∧s would depend on the value of the variable x. Since there are an infinite number of replacement values for x, you cannot list all the truth values for r∧s in the truth table. However, you can find the truth value of r∧s for the given values of x as follows:

If x = 3, r is true, and s is true. Hence, the conjunction r∧s is true.

If x = 9, r is true, and s is false. Hence, the conjunction r∧s is false.

If x = 2, r is false, and s is true. Hence, the conjunction r∧s is false.

If x = 6, r is false, and s is false. Hence, the conjunction r∧s is false.

 x Value Input r Input s Output r AND s (r∧s) 3 True True True 9 True False False 2 False True False 6 False False False

Example 2:

Find the negation of the given statement:

Number 4 is an even number

Solution:

Consider P to be the given statement

Hence, P = 4 is an even number.

Therefore, the negation of the statement is given as

∼S = 4 is not an even number.

Hence, the negation of the statement is that 4 is not an even number.