A certified three-equilibrium bound for 375 fixed quadratic zero-one reaction networks

Article v1 and exact certificates for at most three distinct positive equilibria, including degenerate equilibria, at all positive rate constants in the fixed 375-network list of Tang and Zhang. Includes 375 Cramer reductions, a second resultant route checked with explicit Sylvester determinants, a post-selected finite structural observation, and one seven-reaction family with a rational witness. The original enumeration, 373/2 classification, exceptional identifiers and Lemma 3 are Tang–Zhang results; the original enumeration and the 373-network stability classification are not reverified here. Upstream raw data are not bundled; their pinned input is fetched and hashed. No priority, proof-assistant assurance or human peer review is claimed. Original prose and derived certificates: CC BY 4.0. Code: Apache 2.0. The related two-network collection is available as version 1.0.0, DOI 10.5281/zenodo.23659209 (all versions: 10.5281/zenodo.23659208). Publication identifiers for this 375-network package are pending.