{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"a4724a2e57a420731fe26ca7cbef1fd7e2f67033bcf2268af59c2058927e94c6","created":"2026-10-03T07:18:09Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011","7782085eaddc39411a355e2fffaea013881adc680060419aa177666914f1ab4e"],"salt":"4be0b3200b593323b9c72428cdd4b958ccc95332be2d03ca153f0c11514ddf7b","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"qft.string-nonperturbative.ikkt-four-dims","kind":"well-posed","literature_status":"contested","n":"1","parents":[{"note":"","parent_revision":"7782085eaddc39411a355e2fffaea013881adc680060419aa177666914f1ab4e","relation":"special_case"}],"plain":"A model built from ten large matrices is proposed as a complete definition of one string theory. Whether it produces a universe with three large expanding space directions is unknown.","posed_since":"1996","precise":"The type IIB (IKKT) matrix model of ten $N$ x N Hermitian bosonic matrices and fermions is proposed as a nonperturbative definition of type IIB string theory. Determine whether its Lorentzian version at large N dynamically generates a smooth expanding $(3+1)$-dimensional spacetime with $\\mathrm{SO}(9) \\to \\mathrm{SO}(3)$ breaking, rather than singular configurations.","problem_ref":null,"references":"","settled_by":"Large-N simulations of the Lorentzian model with controlled sign-problem treatment showing (or excluding) smooth emergent 3+1 expansion.","status_note":"Early Lorentzian simulations (2012) reported three expanding directions; later work found singular Pauli-matrix-like structures tied to approximations, and complex Langevin studies continued through 2025.","title":"Do four expanding spacetime dimensions emerge in the IKKT model","topic_ref":"77b6787c01ad201a13194ef87168eea66a0756da2a9a351dc5d7a1594827efd5"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"76ffc5ac426ef9ddc70ca9a2f6ee7096703c16cee697d42bac3ecc38d658871b","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"0b1e75d2ba51ac6910d2b286698e9ef769393b32f47c821ee4bd6685ca189970","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"1zR67ZZrhhSDjoPV_oue-Eu20XeCYiYe_BaqbPexwFL2RGqMeJT0qyZ4EPNBXa3lP8eY72WlCHXDm8AaAL9sBw"},"schema":"pubphys.envelope/1"},"record_hash":"76ffc5ac426ef9ddc70ca9a2f6ee7096703c16cee697d42bac3ecc38d658871b","leaf_index":1956}