Thank you. Seek clarity ... Of the four following assertions about a case, only one is true

This question examines the choice proposition in formal logic. Theory, you search for it yourself. I explain it in layman's terms, because only one conclusion is true (each of the four options is incompatible) is based on the method of elimination:

If (2) is correct, it cannot be ruled out because it has nothing to do with the other three options, so (2) is not true;

If (3) is true, (3) is not true because it cannot exclude (4);

If (4) is true, (4) is not true because it cannot rule out (3);

Therefore, (3) is wrong, so if A in (1) is false, that is, B is not an accomplice. It can also be understood in this way: (1) If A commits the crime, then B is an accomplice = if not A commits the crime, then B is not an accomplice. Fully judged to be true.

Because there is only one truth, and if A commits the crime in (3) and (4), then (3) and (4) are both true, which does not match the meaning of the title. Therefore, (3) and (4) are false. The perpetrators of the rollout are not A and D.

1) and (2) are compared, if (2) is true, and (1) and (2) are not mutually exclusive, so (1) can also be true, for example, if A does not commit the crime, B does not commit the crime. In this way, there are two truths, which do not match the meaning of the title.

Therefore, according to the method of exclusion, only (1) is true. Further, the perpetrator should be B.

1 said that bai is wrong, and 3 says that it is right, that is, ab is not.

zhi criminal (this is a known condition for the back), this conclusion does not need to be explained.

Problem 2, let's assume that C is a criminal and D is not a criminal:

1) From the perspective of the sentence, C is a criminal, so the sentence of 2 "if" is not valid at all, is this considered wrong? Hence the assumption holds.

2) Let's consider the content again, if we assume that C is not a criminal according to 2, and we know that AB is definitely not a criminal (meaning that the criminal must be in CD), then on the basis of the assumption of 2, isn't D a criminal, then his words (if C is not a criminal, D is not) can still be considered right?

So we get the answer assuming that C is the offender, 1 and 2 are wrong, and 3 is right.

As for assuming that D is a criminal, there is no need to be wordy, and a few friends who choose B want to know why they directly pm me.

Finally, add an answer, CD complicity, because the title does not say how many people committed crimes. Note 2 is a hypothetical sentence.

As mentioned earlier, there are three possible answers, C, D, and CD complicity.

What's going on upstairs? Have you reviewed the question? Have you ever learned logical operations? "AB is an accomplice" is the condition given. i.e., it is known that a=b.

a=1 → b=1。 a=0 → b=0。

a=1, b=0 is false.

Therefore, A is the perpetrator and B is not the perpetrator and is false. This proposition is incorrect.

They are all perpetrators, one mastermind, one accomplice.

This reasoning is incorrect. After investigation, it was determined that A was the perpetrator of the crime, and there was no direct relationship between whether B was the perpetrator or not. It needs to be added that A and B have nothing to do with each other in the present case in order to be conclusive.

Well,This can only be said to be not rigorous.,There's one less big premise.。。 For example, the main premise: there is only one perpetrator in this case.

Minor premise: A is the perpetrator and it can be concluded that B is not the perpetrator. And the first sentence of this question seems to imply that there can be more than one perpetrator in this case, so this reasoning should be incorrect, and B is still suspicious...

I'll ask you one more question:

Tomorrow is September 1st, and there is a 50% chance that tomorrow will be a holiday, why, because tomorrow will be either a class or a holiday, so each will account for 50%.

This type of reasoning is called dilemma reasoning. You can check it out.