{"id":"palomar/PALOMAR-2026-09-01-000002","url":"https://github.com/savarin/lean-operator-theory/tree/6f90bb7e6b056b54f56005e0416d77d6d7c2a478","json":"https://data.palomar-registry.org/entries/PALOMAR-2026-09-01-000002-v1.json","repo":"https://github.com/savarin/lean-operator-theory","tags":["math.FA","math.OA","msc:47A12","msc:47A20","msc:47A25","msc:47A30","functional-analysis","operator-theory","lean","numerical-range"],"score":0,"title":"lean-operator-theory","trust":"high","domain":"math.FA","source":"palomar","authors":["Ezzeri Esa"],"reviews":0,"subject":"math.FA","summary":"Hilbert-space operator theory from unitary power dilation through von Neumann's polynomial inequality, together with the Crouzeix--Palencia theorem that the closed numerical range is a (1 + square-root-of-2)-polynomial spectral set.","category":"research","comments":0,"disputed":false,"division":"math","mentions":0,"verified":true,"discussed":0,"published":"2026-09-01","reactions":{},"formalized":true,"formalizes":[{"title":"The numerical range is a (1+sqrt 2)-spectral set","identifier":"10.1137/17M1116672","relationship":"adapts"},{"title":"Harmonic Analysis of Operators on Hilbert Space","identifier":"10.1007/978-1-4419-6094-8","relationship":"formalizes"},{"title":"Remarks on the Crouzeix--Palencia proof that the numerical range is a (1+sqrt 2)-spectral set","identifier":"10.1137/17M1143757","relationship":"adapts"}]}