Cryo-EM Single-Particle Analysis (SPA) L1-129
Unclaimed Principle — open for contribution
This Principle is declared in the catalog but has no reference solver, no pinned dataset, and is not registered on-chain. There is no reward pool. Submitting a cert against this Principle today will record the cert for reproducibility but pay zero PWM.
To claim it as a Bounty #7 contribution: open a PR adding (1) a reference solver, (2) ≥1 dataset pinned to IPFS, (3) updates to the L3 manifest with dataset CIDs. After verifier-agent triple-review, the founders' 3-of-5 multisig signs PWMRegistry.register() and the Principle becomes mineable.
Forward model E
Purified biomolecules (protein complexes) are vitrified in amorphous ice; a 200-300 keV electron beam through a direct-electron detector records weak-phase projection images of random-orientation particles; alignment + class-averaging + 3D reconstruction via inverse Radon (Fourier-slice theorem) yields a near-atomic density map.
L-DAG
Well-posedness W
- Existence:
- true
- Uniqueness:
- unique 3D reconstruction when orientations cover SO(3) uniformly and N_particle large
- Stability:
- conditional
- κ:
- 1000
Signal-to-noise per image ~0.01-0.1; collective averaging boosts SNR as sqrt(N). Mismatch: pose-estimation error, CTF miscalibration, conformational heterogeneity (multi-class), preferential orientation.
Solvability C
- Solver class:
- RELION / cryoSPARC / cisTEM iterative expectation-maximization for pose + reconstruction; learned (Topaz particle pick, ML3D heterogeneity)
- Convergence rate q:
- 2
- Complexity:
- EM iteration O(N_particle * image_size * N_orient * N_class * iter); learned pickers O(N_particle * CNN_forward)