ELI5: Explain Like I'm 5

Biconditional introduction

Okay, imagine you and your friend have a special secret code that you use to send messages to each other. This code is like a biconditional introduction in math.

When you want to use your code to say something like "I'll come play outside with you only if it's sunny," you would write it like this: "I'll come play outside with you if and only if it's sunny."

That's similar to how biconditional introduction works in math. It's a way of saying that two things are true at the same time and depend on each other.

For example, let's say you're trying to prove that two statements, A and B, are equivalent. This means that if one statement is true, the other statement must also be true, and vice versa.

To show that these two statements are equivalent using biconditional introduction, you would first say, "if A is true, then B must be true as well." And then you would also say, "if B is true, then A must also be true."

That's similar to how you and your friend use your secret code to send messages that depend on each other. It's a way of making sure that both of you understand what the other person is saying, and that you're both on the same page.