what is a biconditional statement

A biconditional statement means that the statement and its converse are both true.

If both of the following statements are true,
If he is alive, he respires.
If he respires, he is alive.
then we use the single following statement to say the same thing:
"He is alive if and only if (iff) he respires" which means that the converse is also true:
"If he respires, he is alive".

So being alive is a "necessary and sufficient condition" for "respiring".

See
http://atheism.about.com/library/glossary/general/bldef_biconditional.htm
for more examples and explanations.

A biconditional statement is a logical statement that combines two statements using the "if and only if" (iff) condition. It asserts that the two statements are either both true or both false. It can be written as "p if and only if q" or "p ↔️ q." The statement is true when both p and q have the same truth value, and it is false when they have different truth values.

A biconditional statement is a type of logical statement that connects two statements using the "if and only if" condition. It expresses that two statements are true or false under the exact same conditions. In mathematical notation, a biconditional statement is typically represented by the symbol "⇔" or "↔".

To understand what a biconditional statement is, let's break it down further:

1. "If" part: This represents the first statement that serves as a condition or assumption.
2. "Only if" part: This represents the second statement that is the result or consequence of the first statement.
3. "If and only if": This means that both the first and the second statements are true or false not just individually, but together and only when they are both true or both false.

To determine the truth value of a biconditional statement, you need to evaluate the truth values of both the "if" part and the "only if" part. If both parts are true or both parts are false, then the biconditional statement as a whole is true. However, if either part is true and the other part is false, then the biconditional statement is false.

For example, consider the biconditional statement: "I will eat dessert if and only if I finish my dinner." If you finish your dinner and also eat dessert, then the biconditional statement is true. However, if you finish your dinner but do not eat dessert, or if you do not finish your dinner but still eat dessert, then the biconditional statement is false.