anticommutator function does not simplify for majoranaoperators with multiple arguments

[hepzanechen]

Description:

The anticommutator function does not simplify to 0 for majoranaoperators with multiple arguments if their arguments are different, but it correctly simplifies to 1 for the cases with the same arguments.

Steps to Reproduce:

1. Load the SNEG package and define Majorana operators:

   << sneg`sneg`;
   snegmajoranaoperators[gamma];

2. Compute the anticommutator of two Majorana operators with multiple arguments:

   anticommutator[gamma[2, 1], gamma[3, 0]]
   anticommutator[gamma[2, 1], gamma[2, 1]]

3. Observe the result:

   Out: acmt[gamma[3, 0], gamma[2, 1]]
   Out: 1

---

My workaround is to convert majorana operators with multiple arguments to operators with a single argument, see the following.

1. Define a custom Majorana operator using a delayed function and compute the anticommutator:

   \[Gamma][idx1_, idx2_] := gamma[idx1*2 + idx2];
   anticommutator[\[Gamma][2, 1], \[Gamma][3, 0]]
   anticommutator[\[Gamma][2, 1], \[Gamma][2, 1]]

2. Observe the result:

   Out: 0
   Out: 1

Version: sneg 2.0.5