The top half of this posting is a response to the issue of whether this posting is itself a duplicate of a pre-existing MathSE Meta posting.
The issue was raised whether this posting is a duplicate of this already existing MathSE Meta posting.
No, this posting is not a duplicate of the previous posting. I reviewed the previous posting and saw that it debated whether specific MathSE postings should or should not be considered duplicates. From what I could perceive (perhaps wrongly), the presumption is that there is an existing standard that should be followed. So, the discussion with respect to specific postings revolved around whether the specific standard was or was not being violated.
The thrust of this posting is totally different. There seems (perhaps only in my imagination) to be a disagreement about what the actual standard should be with respect to characterizing a question as a duplicate. The characteristics that seem relevant are:
How similar is the question to a pre-existing question?
How different is the question to a pre-existing question?
How important is it that the question should be of general interest?
Are solution verification questions to be generally regarded as less worthwhile to preserve?
If an original poster presents a question that shows significant work, and asks a solution verification question whose background is very similar to a pre-existing question, should MathSE reviewers be discouraged/prevented from answering?
For example, should the question be closed under the pretense of duplication, with MathSE reviewers prevented from answering, because solution verification questions, by their very nature, are not of general interest?
If an original poster presents a question that shows significant work, and asks a solution verification question whose background is very similar to a pre-existing question, is it reasonable to refer the original poster to the pre-existing question and leave the original poster to self-diagnose whether his alternative approach is accurate/valid?
The remainder of this posting is the original Meta posting, after the editing of Calvin Khor.
The following question was closed as a duplicate: the question. Subsequently, the question was re-opened.
My contention is that:
Since the original poster was specifically asking where he went wrong (with his direct approach), and had already indicated a knowledge of an Inclusion-Exclusion solution, then his posting is not a duplicate of the underlying question.
While there is some value in a posting that demonstrates the pitfalls of a direct approach, even if that was not the case, there is no valid reason to close the question.
On CURED, a rebuttal idea was voiced that the question is not of general interest to MathSE, and therefore should be closed. My reply was that there is no specific guideline that says that only Math problems that are of general interest should remain open.
The rebuttal to my opinion was that the underlying philosophy of MathSE is that such questions should be closed, regardless of the quality of the question itself (i.e. re showing work), and regardless of whether the question actually is a duplicate.
MathSE doesn't belong to me. This is your forum, so please voice your opinions. Let your opinions dictate how such situations will be handled in the future.