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Proof by contradiction is a method of mathematical or logical proof in which we assume the opposite of what we are trying to prove and then show that this assumption leads to a contradiction or an absurdity. From this contradiction, we can conclude that our original assumption must have been false, and therefore, the statement we were trying to prove is true.
Proof by contradiction is often used to prove statements that are difficult to prove directly or to show that a statement is logically necessary. It is also commonly used in mathematics to prove the uniqueness of a solution to a problem.
The process of proof by contradiction involves assuming the opposite of what we are trying to prove, then using logical reasoning and known facts to show that this assumption leads to a contradiction. This contradiction then allows us to conclude that our original assumption must have been false, and therefore, the statement we were trying to prove is true.
Proof by contradiction can be a powerful tool in mathematics and logic as it allows us to prove statements that may be difficult to prove directly. It also helps to show the logical necessity of a statement, and can often lead to more elegant and concise proofs.
While proof by contradiction can be a useful method of proof, it is not always applicable. It relies heavily on the principle of non-contradiction, which states that a statement and its opposite cannot both be true at the same time. In some cases, this principle may not hold, making proof by contradiction an invalid method of proof.