§4 · Agent 4 · Sheaf–function dictionary · 2026-10-17T02:40:19Z
Summary 4.13 · Verdict: one direction is a theorem, the other fails formally; Table 1 rows decided under D0–D5The standing inputs of the sheaf–function dictionary over F̄_q, p ≠ 2: D0 Chen–Yi's orbit geometry; D1 traces of Frobenius and the perverse t-structure; D2 decomposition of Satake objects into shifted IC sheaves; D3 Lang's theorem; D4 unitriangularity of Satake traces; D5 comparison of F̄_q with C.
partial audit: minor defect
Collects the track's results: (SG) over \(\F_q(\!(t)\!)\) implies \(\Csat=\cC_K\) when \(Z_{G^\theta}(S)\) is connected, the converse is not a consequence of the dictionary, the function level holds over \(\F_q(\!(t)\!)\) under Proposition III's conditions, \(\GL_4/\Sp_4\) holds at both levels and \(\SL_2/\SO_2\) fails at the sheaf level. No row exhibits a divergence; the \(p\)-adic entries remain incomparable.
Summary 4.13.
Theorems (symmetric \(X\) with \(G^\theta\) connected over \(\F_q\), \(q\) odd, \(T\) split; modulo D0–D4The standing inputs of the sheaf–function dictionary over F̄_q, p ≠ 2: D0 Chen–Yi's orbit geometry; D1 traces of Frobenius and the perverse t-structure; D2 decomposition of Satake objects into shifted IC sheaves; D3 Lang's theorem; D4 unitriangularity of Satake traces; D5 comparison of F̄_q with C. of Setup 4.1, plus D5D5 · Comparison with C: “IC_μ is a summand of V_λ ∗ IC_0” has the same answer over F̄_q and over C (BBD §6.1, for large p). for statements over \(\C\)):
- Theorem 4.6: \(Z_{G^\theta}(S)\) connected and (SG) over \(\F_{q^n}(\!(t)\!)\) for one \(n\) \(\Rightarrow\) \(\Csat=\cC_K\).
- Proposition 4.7: \(\Csat=\cC_K\Rightarrow\) every \(\IC_\mu\) is detected by some Hecke translate over some \(\F_{q^n}(\!(t)\!)\); this is strictly weaker than (SG), and "\(\Csat=\cC_K\Rightarrow\)(SG)" is not a consequence of the dictionary (retract closure versus the Grothendieck group; the shape of Sakellaridis's Example 8.0.1).
- Lemma 4.8: the two conditions of Proposition III \(\Rightarrow\) (SG) over \(\F_q(\!(t)\!)\), without (A)“Under (A)”: assuming all of Sakellaridis's assumptions (A1)–(A5) for X at the given p-adic place, so that his Theorem 8.0.2 applies..
- Theorem 4.9: \(\GL_4/\Sp_4\): (SG) over \(\F_q(\!(t)\!)\) (explicit; machine-checked for \(q=3,5\), proved for all \(q\)), hence \(\Csat=\cC_K\).
- Theorem 4.11: \(\SL_2/\SO_2\): \(\Csat\ne\cC_K\).
Table 1 updates (sheaf column; function column for \(F=\F_q(\!(t)\!)\)):
| \(X\) | sheaves | functions over \(\F_q(\!(t)\!)\) |
|---|---|---|
| group, spheres (all \(n\)), \(\GL_n/(\GL_p\times\GL_q)\), \(\GL_2/\Sp_2\), \(\SL_4/\Sp_4\) | equal (I, III; unchanged) | holds (Lemma 4.8; was open for spheres \(n\ge4\), under (A)“Under (A)”: assuming all of Sakellaridis's assumptions (A1)–(A5) for X at the given p-adic place, so that his Theorem 8.0.2 applies. otherwise) |
| \(\GL_4/\Sp_4\) | equal (Theorem 4.9 and Theorem 4.6; was unknown) | holds (Theorem 4.9) |
| \(\GL_{2m}/\Sp_{2m}\) (\(m\ge3\)), \(\SL_{2n}/\Sp_{2n}\) (\(n\ge3\)) | unknown; decided by (SG) over \(\F_q(\!(t)\!)\) via Theorem 4.6 | open over \(\F_q(\!(t)\!)\) (Dead end 4.10, Objection 4.12); (A)“Under (A)”: assuming all of Sakellaridis's assumptions (A1)–(A5) for X at the given p-adic place, so that his Theorem 8.0.2 applies. is \(p\)-adic only |
| \(E_6/F_4\) | unknown; same reduction | open |
| \(\SL_2/\SO_2\) | not equal (Theorem 4.11; was undecided) | fails (Proposition J; re-derived from stabilizers, Lemma 4.2) |
| \(\GL_n/\mathrm O_n\), \(\PGL_2/\mathrm{PO}_2\) | not equal (unchanged) | fails (unchanged) |
Answer to the question. For symmetric \(X\) on these pages with \(Z_{G^\theta}(S)\) connected, no divergence of the form "(SG) over \(\F_q(\!(t)\!)\) holds but \(\Csat\ne\cC_K\)" is possible (Theorem 4.6). A divergence of the form "\(\Csat=\cC_K\) but (SG) fails" is not excluded by the dictionary (Proposition 4.7), but no row exhibits it: wherever the sheaf level is known to be equal, the function level over \(\F_q(\!(t)\!)\) holds (Lemma 4.8, Theorem 4.9); where (SG) fails (\(\SL_2/\SO_2\), disconnected \(G^\theta\)), the sheaf level fails too (Theorem 4.11, split forms). The \(p\)-adic "(SG) under (A)“Under (A)”: assuming all of Sakellaridis's assumptions (A1)–(A5) for X at the given p-adic place, so that his Theorem 8.0.2 applies." entries remain incomparable with the sheaf level (Objection 4.12). Gap: D0–D5The standing inputs of the sheaf–function dictionary over F̄_q, p ≠ 2: D0 Chen–Yi's orbit geometry; D1 traces of Frobenius and the perverse t-structure; D2 decomposition of Satake objects into shifted IC sheaves; D3 Lang's theorem; D4 unitriangularity of Satake traces; D5 comparison of F̄_q with C. of Setup 4.1, and the finite computations of Dead end 4.10.
- The theorem direction. A nonzero Frobenius trace coefficient forces a nonzero multiplicity space, so spherical generation over \(\F_q(\!(t)\!)\) puts every \(\IC_\mu\) into the thick span (Theorem 4.6).
- The converse. It would need a statement in the Grothendieck group — for each uncovered label, a Hecke combination supported in its lower set — which closure under retracts cannot supply (Proposition 4.7).
- The decided rows. \(\GL_4/\Sp_4\) is decided at both levels in the same field by two lattice counts and the transfer theorem (Theorem 4.9); \(\SL_2/\SO_2\) by the square-class automorphism read through the dictionary (Theorem 4.11); the rows satisfying Proposition III's conditions gain an (A)“Under (A)”: assuming all of Sakellaridis's assumptions (A1)–(A5) for X at the given p-adic place, so that his Theorem 8.0.2 applies.-free function level over \(\F_q(\!(t)\!)\) (Lemma 4.8).
Builds on
- Theorem 4.6 · Theorem: (SG) over \(\F_q(\!(t)\!)\) implies \(\Csat=\cC_K\) over \(\overline{\F}_q\)
- Proposition 4.7 · The converse fails in general: \(\Csat=\cC_K\) gives detection by Hecke translates, not spherical generation
- Lemma 4.8 · Under the two conditions of Proposition III, (SG) holds over \(\F_q(\!(t)\!)\) without Sakellaridis's hypotheses
- Theorem 4.9 · \(\GL_4/\Sp_4\): the uncovered label \((1,1,1,1)\) is reached by Hecke translates, so (SG) holds over \(\F_q(\!(t)\!)\) and \(\Csat=\cC_K\)
- Dead end 4.10 · \(\GL_6/\Sp_6\) at the label \((1,1,1,1,0,0)\): the three in-box translates do not suffice; a larger box is needed
- Theorem 4.11 · \(\SL_2/\SO_2\): the sign-twisted IC sheaves are not in the Satake span, so \(\Csat\ne\cC_K\) over \(\overline{\F}_q\)
- Objection 4.12 · Obstacles: \(\C\) versus \(\overline{\F}_q\), characteristic \(0\) in (A1)(A1) Field and group: F is a local field of characteristic 0 (p-adic), and G is split over the integers, with connected fibres and simply connected derived group. Its characteristic-p counterpart is (A1ₚ). versus \(\F_q(\!(t)\!)\), Weil versus geometric, eigenvalue cancellation
Built on by
- Objection 7.17 · Objection: three cells of the status classification disagree with other results and must be updated
- Audit 7.18 · Audit of the remaining checklist items: heuristic labels are honest, and two verdict sentences need the field caveat
- Re-derivation X1.5 · (SG) for GL₂ₘ/Sp₂ₘ re-derived from Lemmas 2–3 alone; A4-13's open cells now decided
- Summary X2.8 · Re-derivation of Summary 4.13, Summary 7.19, Summary 7.25, Summary 7.32 from the repaired steps
- Strategy 9.1 · Registry after three first-round returns: \(E_6/F_4\) declared the only live divergence; an auditor and an \(E_6/F_4\) sheaf attack are launched
Original record, as the agent wrote it at 02:40 UTC
Verdict: one direction is a theorem, the other fails formally; Table 1 rows decided under D0-D5
Theorems (all for symmetric \(X\) with \(G^\theta\) connected over \(\mathbb F_q\), \(q\) odd, \(T\) split, modulo D0–D4, plus D5 for statements over \(\mathbb C\)).
- (A4-6) \(Z_{G^\theta}(S)\) connected and (SG) over \(\mathbb F_{q^n}(\!(t)\!)\) for one \(n\) \(\Rightarrow\mathcal C^{\mathrm{Sat}}=\mathcal C\).
- (A4-7) \(\mathcal C^{\mathrm{Sat}}=\mathcal C\Rightarrow\) every \(\mathrm{IC}_\mu\) is detected by some Hecke translate over some \(\mathbb F_{q^n}(\!(t)\!)\); this is strictly weaker than (SG), and the implication "\(\mathcal C^{\mathrm{Sat}}=\mathcal C\Rightarrow\)(SG)" is not a consequence of the dictionary (retract-closure vs \(K_0\); Example 8.0.1 shape).
- (A4-8) Prop. III's two conditions \(\Rightarrow\) (SG) over \(\mathbb F_q(\!(t)\!)\), no (A).
- (A4-9) \(\mathrm{GL}_4/\mathrm{Sp}_4\): (SG) over \(\mathbb F_q(\!(t)\!)\) (explicit, machine-checked for \(q=3,5\), proved for all \(q\)), hence \(\mathcal C^{\mathrm{Sat}}=\mathcal C\).
- (A4-11) \(\mathrm{SL}_2/\mathrm{SO}_2\): \(\mathcal C^{\mathrm{Sat}}\ne\mathcal C\).
Table 1 updates (sheaf column; function column for \(F=\mathbb F_q(\!(t)\!)\)).
| \(X\) | sheaves | functions over \(\mathbb F_q(\!(t)\!)\) |
|---|---|---|
| group, spheres (all \(n\)), \(\mathrm{GL}_n/(\mathrm{GL}_p\times\mathrm{GL}_q)\), \(\mathrm{GL}_2/\mathrm{Sp}_2\), \(\mathrm{SL}_4/\mathrm{Sp}_4\) | equal (I, III; unchanged) | holds (A4-8; was open for spheres \(n\ge4\), under (A) otherwise) |
| \(\mathrm{GL}_4/\mathrm{Sp}_4\) | equal (A4-9 + A4-6; was unknown) | holds (A4-9) |
| \(\mathrm{GL}_{2m}/\mathrm{Sp}_{2m}\) \(m\ge3\), \(\mathrm{SL}_{2n}/\mathrm{Sp}_{2n}\) \(n\ge3\) | unknown; decided by (SG) over \(\mathbb F_q(\!(t)\!)\) via A4-6 | open over \(\mathbb F_q(\!(t)\!)\) (A4-10, A4-12.2); (A) is \(p\)-adic only |
| \(E_6/F_4\) | unknown; same reduction | open |
| \(\mathrm{SL}_2/\mathrm{SO}_2\) | not equal (A4-11; was undecided) | fails (J; re-derived from stabilizers, A4-2) |
| \(\mathrm{GL}_n/\mathrm O_n\), \(\mathrm{PGL}_2/\mathrm{PO}_2\) | not equal (unchanged) | fails (unchanged) |
Answer to the team question. On these pages, for symmetric \(X\) with \(Z_{G^\theta}(S)\) connected, no divergence of the form "(SG) over \(\mathbb F_q(\!(t)\!)\) holds but \(\mathcal C^{\mathrm{Sat}}\neq\mathcal C\)" is possible (A4-6). A divergence of the form "\(\mathcal C^{\mathrm{Sat}}=\mathcal C\) but (SG) fails" is not excluded by the dictionary (A4-7) but no row exhibits it: wherever the sheaf level is known to be equal, the function level over \(\mathbb F_q(\!(t)\!)\) holds (A4-8, A4-9); where (SG) fails (\(\mathrm{SL}_2/\mathrm{SO}_2\), disconnected \(G^\theta\)), the sheaf level fails too (A4-11, split-forms). The \(p\)-adic "(SG) under (A)" entries remain incomparable with the sheaf level (A4-12.2). Gap: D0–D5 as listed in A4-1, and the finite computations of A4-10.
Sources
- /Users/miltonlin/Projects/Trees/subpages/case-study-1-ramifiedrelative/proof_graphs/spherical-generation/summary.html Table 1, §4