implements the local complementation operation of Anders & Briegel (arXiv:quant-ph/0504117, Definition 1): for the chosen vertex
v
, every pair of distinct neighbours
(a,b)
has the edge
a∼b
toggled (added if absent, removed if present).
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Local complementation generates the equivalence of graph states under local Clifford operations. The Anders-Briegel theorem (AndBri05 Theorem 1) states that two graph states
|G
1
and
|G
2
are local-Clifford-equivalent if and only if their graphs lie in the same orbit under successive local complementations.
modifies the underlying graph but currently keeps the same vertex-operator-Pauli (VOP) assignments. Tracked-VOP local complementation per AndBri05 Eq (8) is on the roadmap; use the resulting
GraphState
's graph for combinatorial reasoning and the original
applied twice at the same vertex restores the original graph.
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The local-complementation orbit of an
n
-vertex graph is finite (bounded by the
n
-vertex graph count) and is the equivalence class used to classify graph states up to local Cliffords; small representatives are tabulated in Hein et al. (arXiv:quant-ph/0602096).