§3 · Agent 3 · Symplectic family: fibres · 2026-10-17T02:48:26Z

Summary 3.11 · Verdict for the symplectic family: no disagreement between the levels; \(\GL_4/\Sp_4\) settled at both

proved audit: error

Error. Point 1 is correct. Point 2's bold claim 'No disagreement can occur' for GL_{2m}/Sp_{2m} (m >= 3) and SL_{2n}/Sp_{2n} (n >= 3) is not established by the argument given. The first exclusion uses Proposition 3.10, whose hypothesis is (SG) over F_q((t)); the second uses Proposition F, a p-adic result under (A1)-(A5)Sakellaridis's standing assumptions for his Theorem 8.0.2 (the pages' Theorem E): (A1) a characteristic-0 field and a split group with simply connected derived group; (A2) an integral model of X with a smooth open Borel orbit and invariant measures; (A3a) rank-one models over O, (A3b) the Cartan decomposition, (A3c) Iwahori orbits (his Axioms 2.2.1, 2.4.1, 2.4.2); (A4) conditions on the spherical roots and colours; (A5) X homogeneous and affine with one open Borel orbit., and Proposition 3.10's own Remark (b) says Theorem E is not available over F_q((t)). For no single field are both exclusions available. Over a p-adic F, '(SG) holds and Csat != C' is not excluded: Proposition 3.10 does not apply, and 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. (SG) does hold p-adically while the sheaf level is only partial. Over F_q((t)), 'Csat = C and (SG) fails' is not excluded. The node's caveat covers the dependence on (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., not this change of field, so the row was undecided at the time: a result moved across fields without the bridge, inside a verdict marked proved. The conclusion is nevertheless true by a later argument. Theorem 5.7 proves (SG) over every non-archimedean F for all m (with the SL corollary), so Proposition 3.10 applies over F_q((t)), q odd, and gives Csat = C over F_q-bar (Betti via the transfer item); both levels hold (Audit 7.23). The conclusion still holds by another argument.
Corrected by: Audit 7.18 · Audit of the remaining checklist items: heuristic labels are honest, and two verdict sentences need the field caveat, Audit 7.23 · Audit of the \(\GL_{2m}/\Sp_{2m}\) theorem: the induction holds (directly, not through Proposition B as stated); the \(\SL\) corollary and the sheaf consequence hold.

Records that \(\GL_4/\Sp_4\) satisfies both statements: sheaves by the closed-orbit retract and the scalar shift, functions unconditionally over every local field. For larger ranks the sheaf level is partial, and the node concludes that no disagreement can occur, combining the trace implication over \(\F_q(\!(t)\!)\) with Sakellaridis's theorem over \(p\)-adic fields under (A1)–(A5)Sakellaridis's standing assumptions for his Theorem 8.0.2 (the pages' Theorem E): (A1) a characteristic-0 field and a split group with simply connected derived group; (A2) an integral model of X with a smooth open Borel orbit and invariant measures; (A3a) rank-one models over O, (A3b) the Cartan decomposition, (A3c) Iwahori orbits (his Axioms 2.2.1, 2.4.1, 2.4.2); (A4) conditions on the spherical roots and colours; (A5) X homogeneous and affine with one open Borel orbit..

Summary 3.11.

  1. \(\GL_4/\Sp_4\) (Table 1 row "H5H5 · Nonzero top splitting: for every orbit O_μ some Satake object V_λ ∗ IC_0 is supported on its closure with a nonzero split restriction to O_μ. fails by coverage → unknown"): both levels hold. Sheaves: \(\IC_{(1,1)}=\Delta_{(1,1)}\) is a retract of \(V_{\omega_2}\ast\IC_0\) (Proposition 3.3); all odd \((a,a)\) follow by the scalar shift \(\sigma\) and central translation (Theorem 3.6); covered labels by Proposition III, step 6; so \(\mathcal M=\Lambda_S^+\) and \(\Csat=\cC_K\) by the summand criterion (Proposition 3.4), modulo the inputs Proposition III already uses (decomposition theorem for Satake objects in \(\cC_K\), transfer from ℓ-adic to Betti sheaves). Functions: (SG) holds over every non-archimedean local field with no hypothesis (Theorem 3.9). The Table-1 entry should read "holds (retract, not H5H5 · Nonzero top splitting: for every orbit O_μ some Satake object V_λ ∗ IC_0 is supported on its closure with a nonzero split restriction to O_μ.)".
  2. \(\GL_{2m}/\Sp_{2m}\), \(m\ge3\), and \(\SL_{2n}/\Sp_{2n}\), \(n\ge3\). Sheaf level partial: \(\mathcal M\supseteq\varphi(\Lambda_T^+)\cup\{(1^k0^{m-k})+c,\ (2^{k-m}1^{2m-k})+c\}\) (Theorem 3.6); \(\SL\) reduces to component 0 of \(\GL\) (Lemma 3.7); the smallest \(\SL_6\) label \((1,1,-2)\) is open, with a predicted witness (Conjecture 3.8). Function level as on the pages (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.). No disagreement can occur: (SG) over \(\F_q(\!(t)\!)\) implies \(\Csat=\cC_K\) (Proposition 3.10), so "(SG) holds, \(\Csat\ne\cC_K\)" is impossible; and "\(\Csat=\cC_K\), (SG) fails" is excluded 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. by Proposition F (\(r\) surjective for every \(q\)). Unconditionally the second direction remains open for \(m\ge3\), as does the sheaf level for the labels not listed.
  3. Mechanism. For uncovered \(\mu\) the H5-type inputs are unavailable (Proposition 3.4). What works is a retract supported on a proper closed subset of the support of \(V_\lambda\ast\IC_0\), detected by a non-semismall fibre \(LG(n_1,2n_1)\) at the offending odd pairs: exactly the \(\SL_2\)-grading of the relative Satake picture.
  1. Point 1 assembles the sheaf-level results Proposition 3.3 (the closed-orbit retract), Theorem 3.6 (shift stability, so every \((a,a)\) is reached) and Proposition III, step 6 (covered labels), and applies the summand criterion Proposition 3.4(2). The standing inputs are those of Proposition III: the decomposition theorem for Satake objects and the passage from ℓ-adic to Betti sheaves. The function-level half is Theorem 3.9.
  1. Point 2 collects the partial sheaf-level results of Theorem 3.6, Lemma 3.7, Conjecture 3.8. The claim that no disagreement can occur rests on two implications:The node notes that 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. the second direction is open for \(m\ge3\).
  1. Point 3 reads the mechanism off Proposition 3.3 and Theorem 3.6: the retract appears with the extreme shift at the stratum where the fibre \(LG(n_1,2n_1)\) has maximal defect, matching the \(\SL_2\)-weight in Conjecture 3.8.

Builds on

  • Proposition 3.3 · Decomposition of \(V_{\omega_2}\ast\IC_0\) for \(\GL_4/\Sp_4\): \(\IC_{(1,1)}\) is a retract with multiplicity \(k[2]\oplus k\oplus k[-2]\)
  • Theorem 3.6 · \(\GL_{2m}/\Sp_{2m}\): the labels \((1^k0^{m-k})\), \((2^{k-m}1^{2m-k})\) and their shifts lie in \(\mathcal M\); \(\GL_4/\Sp_4\) is complete
  • Lemma 3.7 · \(\SL_{2n}/\Sp_{2n}\) is the degree-zero component of \(\GL_{2n}/\Sp_{2n}\); its smallest uncovered label stays open
  • Conjecture 3.8 · Relative-Satake prediction of every multiplicity; general uncovered labels and the exact gap
  • Theorem 3.9 · Explicit \(T_{\omega_k}\ast\varphi_0\) over every local field; (SG) for \(\GL_4/\Sp_4\) without Sakellaridis's hypotheses
  • Proposition 3.10 · Function level implies sheaf level: (SG) over \(\F_q(\!(t)\!)\) forces \(\mathcal M=\Lambda_S^+\)

Built on by

Original record, as the agent wrote it at 02:48 UTC

Verdict for the symplectic family: no disagreement between the levels; GL_4/Sp_4 settled at both

  1. \(\mathrm{GL}_4/\mathrm{Sp}_4\) (Table 1 row "H5 fails by coverage → unknown"): both levels hold. Sheaves: \(\mathrm{IC}_{(1,1)}=\Delta_{(1,1)}\) is a retract of \(V_{\omega_2}\ast\mathrm{IC}_0\) (A3-3), all odd \((a,a)\) follow by the scalar shift \(\sigma\) and central translation (A3-6), covered labels by Prop. III step 6, so \(\mathcal M=\Lambda_S^+\) and \(\mathcal C^{\mathrm{Sat}}=\mathcal C\) by the summand criterion A3-4 — modulo the inputs Prop. III already uses (decomposition theorem for Satake objects in \(\mathcal C\), transfer from \(\ell\)-adic to Betti). Functions: (SG) holds over every non-archimedean local field with no hypothesis (A3-9). The Table-1 entry should read "holds (retract, not H5)".
  2. \(\mathrm{GL}_{2m}/\mathrm{Sp}_{2m}\), \(m\ge3\), and \(\mathrm{SL}_{2n}/\mathrm{Sp}_{2n}\), \(n\ge3\): sheaf level partial: \(\mathcal M\supseteq\varphi(\Lambda_T^+)\cup\{(1^k0^{m-k})+c,(2^{k-m}1^{2m-k})+c\}\) (A3-6), \(\mathrm{SL}\) reduces to \(\mathrm{GL}\) component 0 (A3-7), the smallest \(\mathrm{SL}_6\) label \((1,1,-2)\) is open with a predicted witness (A3-8). Function level as on the pages (under (A)). No disagreement can occur: (SG) over \(\mathbb F_q(\!(t)\!)\) implies \(\mathcal C^{\mathrm{Sat}}=\mathcal C\) (A3-10), so "(SG) holds, \(\mathcal C^{\mathrm{Sat}}\ne\mathcal C\)" is impossible; and "\(\mathcal C^{\mathrm{Sat}}=\mathcal C\), (SG) fails" is excluded under (A) by Prop. F (surjective \(r\) for every \(q\)). Unconditionally the second direction remains open for \(m\ge3\), as does the sheaf level for the labels not listed.
  3. Mechanism: for uncovered \(\mu\) the H5-type inputs are unavailable (A3-4); what works is a retract supported on a proper closed subset of the support of \(V_\lambda\ast\mathrm{IC}_0\), detected by a non-semismall fibre (\(LG(n_1,2n_1)\)) at the offending odd pairs, exactly the \(\mathrm{SL}_2\)-grading of the relative Satake picture.

Sources