Structure of "affirming the consequent fallacy"

Question

The formal structure of affirming the consequent fallacy is,

P1 - If A is true, then B is true
P2 - B is true
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C - Therefore, A is true

Now if I give another similar example like, (with a B negation)

P1 - If A is true, then B is true
P2 - B is not true
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C - Therefore, A is not true

Will it still be called affirming the consequent fallacy or is there any special name?

Answer 1

This is just normal Modus_tollens or called denying the consequent of classic logic of syllogism

The form of a modus tollens argument resembles a syllogism, with two premises and a conclusion:

If P, then Q. Not Q. Therefore, not P.

The first premise is a conditional ("if-then") claim, such as P implies Q. The second premise is an assertion that Q, the consequent of the conditional claim, is not the case. From these two premises it can be logically concluded that P, the antecedent of the conditional claim, is also not the case.

Answer 2

That's not a fallacy at all, but a deductive argument form, aka modus tollens.

Answer 3

Since any conditional is equivalent to its contrapositive, P1 is equivalent to "If B is not true, then A is not true." In this form, it should be clear "A is not true" is a valid conclusion, so this is not a fallacy.