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The treewidth is a measure of the count of original graph vertices mapped onto any tree vertex in an optimal tree decomposition.

I wrote Mathematica code to calculate Treewidth based on the Python code provided in the CodeGolf question.

I am now looking for a review in terms of approach, clarity, performance, etc.

eliminationWidth[graph_] := Module[{maxNeighbors = 0, currentGraph = graph, vertices, i, neighbors, newEdges},
  vertices = Union[Flatten[graph]];
  Do[
   neighbors = Union[
     Cases[currentGraph, {a_, i} :> a] ~Join~ 
     Cases[currentGraph, {i, b_} :> b]
     ];
   maxNeighbors = Max[Length[neighbors], maxNeighbors];
   newEdges = Select[Tuples[neighbors, 2], #[[1]] < #[[2]] &];
   currentGraph = Select[currentGraph, FreeQ[#, i] &] ~Join~ newEdges;
   , {i, Sort[vertices]}];
  maxNeighbors
  ]

treewidth[graph_] := Module[{vertices, minWidth, permutations, newGraph},
  vertices = Union[Flatten[graph]];
  minWidth = Length[vertices];
  permutations = Permutations[vertices];
  Do[
   newGraph = graph /. Thread[vertices -> perm];
   minWidth = Min[eliminationWidth[newGraph], minWidth];
   , {perm, permutations}];
  minWidth
  ]

(* Test cases *)
testCases = {
  {{0, 1}, {0, 2}, {0, 3}, {2, 4}, {3, 5}},
  {{0, 1}, {0, 2}, {1, 2}, {1, 4}, {1, 5}, {1, 6}, {2, 3}, {2, 4}, {3, 4}, {4, 6}, {4, 7}, {5, 6}, {6, 7}}
};

expectedResults = {1, 2};

(* Run tests *)
Do[
  result = treewidth[testCases[[i]]];
  Print["Test case ", i, ": Expected ", expectedResults[[i]], ", Got ", result, 
   If[result == expectedResults[[i]], " ✓", " ✗"]];
  , {i, Length[testCases]}]
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