Can anyone explain why the following pattern matches:

[In1]:MatchQ[Hold[a + c + b], Hold[x_ + b + a]]

But this one fails:

[In1]:MatchQ[Hold[c + b + a], Hold[x_ + b + a]]

It seems that the pattern matcher tries all permutations even if the Plus expression is held (case 1), so why does it fail for case 2?

Many thanks for your help

  • 1
    $\begingroup$ related $\endgroup$
    – Lacia
    Feb 15, 2023 at 17:14
  • $\begingroup$ This is an interesting question that seems not to have a simple answer. Maybe you will ask: [email protected] and tell us what they replied. $\endgroup$ Feb 17, 2023 at 16:54


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