If and only if relationship between them?

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In summary, when proving equivalence between definitions, you are essentially showing an "if and only if" relationship between them. This is different from identity, where both sides of an equation are identical. In equivalence, there may be variables involved, but only certain values can make the equation a case of identity. When proving equivalence in logic, it is important to demonstrate an "if and only if" relationship.
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_DJ_british_?
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"if and only if" relationship between them?

Hi Pfers, just a little question :

If you have a problem of the form "Show that these definitions are equivalent",do I basically have to prove an "if and only if" relationship between them?
 
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Equivalence is different from identity in math, in that, if two sides of an equation are equivalent, as opposed to identical, it just means that there are variables involved of which there are only certain values (in place of the variable(s)) that make the equation a case of identity. So, 3+3 = 6 is a case of identity, while 3 + x = 6 is a case of equivalence, since there is a variable involved (to put it simply). x * 0 = 6 is a case of non-equivalence, since both sides of the equation can never be identical.

You seem to be talking about logic, though (and answering a question), so, yes, you'll want to show that an "if and only if" is possible.
 

Related to If and only if relationship between them?

1. What is an "if and only if" relationship?

An "if and only if" relationship, also known as a biconditional relationship, is a logical relationship between two statements where both statements are true or false together. This means that if one statement is true, the other must also be true, and if one statement is false, the other must also be false.

2. How is an "if and only if" relationship different from an "if-then" relationship?

An "if and only if" relationship is bidirectional, meaning that both statements must be true or false together. In contrast, an "if-then" relationship is only unidirectional, meaning that if the first statement is true, the second statement may or may not be true. Additionally, an "if-then" relationship can have a false antecedent (first statement), whereas an "if and only if" relationship cannot.

3. Can an "if and only if" relationship exist between more than two statements?

Yes, an "if and only if" relationship can exist between multiple statements. For example, if A is true if and only if B is true if and only if C is true, then all three statements must be true or false together.

4. How is an "if and only if" relationship used in scientific research?

In scientific research, an "if and only if" relationship is commonly used in hypothesis testing. This is because it allows for a stricter validation of the hypothesis, as both the cause and effect must be true or false together.

5. Can an "if and only if" relationship be used in mathematical proofs?

Yes, an "if and only if" relationship is commonly used in mathematical proofs to show equivalence between two statements. This is because the relationship requires both statements to be true or false together, providing a stronger level of proof than a unidirectional "if-then" relationship.

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