lean t3_m1_stabRank_gt_two in LeanProofs.T3M1StabRank, machine-checked by Lean
This bound is backed by a machine-checked theorem: t3_m1_stabRank_gt_two in LeanProofs.T3M1StabRank. The recorded lake build confirms it compiles.
Settles χ(|T3〉) = 3 with the rank-3 upper bound. On one qutrit there are only 12 stabilizer states, so the rank-2 question is 66 pairs and is decided by exhaustion rather than by the Galois argument, which reaches the same bound at every m but is not yet formalized. The exclusion is numerical and rests on a margin: the closest any two candidate directions come to parallel is 0.956 against a threshold of 1 - 1e-6, so no rounding at the 1e-15 level of these inputs can close the gap. The Strange state at m=1 has a known rank-2 decomposition, which the same code finds as a positive control. Now also proved in Lean, and against stabRank itself: t3_m1_stabRank_gt_two shows Stabilizer.stabRank IsStab |T3〉 > 2 by the Galois argument. T3Galois gives the dimension count (the three conjugates t1, t4, t7 are independent, a Vandermonde), T3GaloisDescent discharges its hypothesis (the span of vectors over Z[ω3] containing t1 contains every conjugate: descend coefficients to Q(ω9), then apply the embedding ω9 → ω9^e for e in {1, 4, 7}, which fixes Z[ω3]), and every IsStab vector is a multiple of a vector over Z[ω3]. The pair exhaustion above remains as the reproduced-tier certificate; the Lean theorem is what the cell now holds.
this repository · stabrank PR #19 · exhaustion over all 66 pairs of 1-qutrit stabilizer states
{
"schema_version": "0.1",
"orbit": "T3",
"m": 1,
"direction": "lower",
"rank": 3,
"certificate": {
"script": "verify_challenge/cert_t3m1_rank2.py",
"expect": "CERTIFIED chi(T3^1) >= 3"
},
"provenance": {
"author": "this repository",
"reference": "stabrank PR #19",
"method": "exhaustion over all 66 pairs of 1-qutrit stabilizer states",
"date": "2026-09-16",
"github": [
"vprusso"
]
},
"notes": "Settles chi(|T3>) = 3 with the rank-3 upper bound. On one qutrit there are only 12 stabilizer states, so the rank-2 question is 66 pairs and is decided by exhaustion rather than by the Galois argument, which reaches the same bound at every m but is not yet formalized. The exclusion is numerical and rests on a margin: the closest any two candidate directions come to parallel is 0.956 against a threshold of 1 - 1e-6, so no rounding at the 1e-15 level of these inputs can close the gap. The Strange state at m=1 has a known rank-2 decomposition, which the same code finds as a positive control. Now also proved in Lean, and against stabRank itself: t3_m1_stabRank_gt_two shows Stabilizer.stabRank IsStab |T3> > 2 by the Galois argument. T3Galois gives the dimension count (the three conjugates t_1, t_4, t_7 are independent, a Vandermonde), T3GaloisDescent discharges its hypothesis (the span of vectors over Z[w3] containing t_1 contains every conjugate: descend coefficients to Q(w9), then apply the embedding w9 -> w9^e for e in {1, 4, 7}, which fixes Z[w3]), and every IsStab vector is a multiple of a vector over Z[w3]. The pair exhaustion above remains as the reproduced-tier certificate; the Lean theorem is what the cell now holds.",
"lean": {
"module": "LeanProofs.T3M1StabRank",
"theorem": "t3_m1_stabRank_gt_two"
}
}