Someone "Copying" your answer after you post it

Question

I was answering this question; after my answer posted, this user edited his/her answer to make it almost identical to mine, but just rearranged the statements $(1)$ and $(2)$ in different order. Should I ask him/her to edit or delete the answer?

Answer 1

I am the user who copied your answer Manx. My original post did not answer the OP’s question, so I edited it to yours.

I apologise for copying your answer without mentioning you. I have edited my answer to give credit to you for the original post, and I have recently visited this page for advice on how, and when to edit an incorrect answer.

---

In retrospect, I should have attributed the original answer to yours in the first place. I did not because I assumed that the time stamp would be enough. This assumption was wrong, and in the future, I will always leave a note or just delete the original answer.

I preferred editing the original answer, because I was taught the distributive law one way (distributing a logical $\land$ over an $\lor$), however your answer and Wikipedia cite it in two forms, where one distributes an $\land$ over an $\lor$, and in the other, an $\lor$ over an $\land$. While I was aware that these two forms existed, I was not aware that the second form was common in logic courses.

I was also not used to using double $ symbols for tagged equations, and had always used \begin{equation}\tag{…} instead. In this way writing the answer was a learning experience for me.

---

Sincerest apologies,

User400188

Answer 2

Comparing the sources of the two answers, it is unlikely that the answer you referred to is "copy-and-paste". In particular, you use \vee while the other one use \lor. (See source code below.)

Timeline:

• The other user posted the first version at 2020-05-17 06:43:07Z,
• you posted yours later at 2020-05-17 18:34:30Z
• The other user then made an edit at 2020-05-18 09:12:22Z with a note: "after understanding the definitions of the distributive law used in the question askers text, I was able to correct the answer."

It is possible that the user saw your answer and figured out they should correct their answer. [If this is the case, I would prefer writing it out explicitly in the edit.]

---

Nevertheless, you have a valid concern. Unethical copying of other's solutions verbatim (repeatedly) did happen on the main site before. If you find repetitive behaviors, you should flag a post.

---

The most current version of the answer you referred to:

The distributive laws $(1~-~2)$ can be applied in two directions.

$$\tag{1}
p\land(q\lor r)\equiv (p\land q)\lor (p\land r)
$$

$$\tag{2}
p\lor(q\land r)\equiv (p\lor q)\land (p\lor r)
$$

Applying $(2)$ from right to left on $(p\lor\sim q)\land(p\lor q)$, yields the desired result $p\lor(\sim q\land q)$.

Your answer:

Distributive laws states that
$${\displaystyle p\vee (q\wedge r)\equiv (p\vee q)\wedge (p\vee r)}\tag{1}$$
$${\displaystyle p\wedge (q\vee r)\equiv (p\wedge q)\vee (p\wedge r)}\tag{2}$$
Here we are applying $(1)$ that $(\color{red}p\vee \color{blue}q)\wedge (\color{red}p\vee \color{green}r)$ implies $\color{red}p\vee (\color{blue}q\wedge \color{green}r)$.

That $(\color{red}p∨\color{blue}{∼q})∧(\color{red}p∨\color{green}q)$ implies $\color{red}p∨(\color{blue}{∼q}∧\color{green}q)$ which is distributing $p$ out.