Magnetic Particle Imaging (MPI) L1-069
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
Magnetic Particle Imaging (MPI): mpi ffp scan produces the measurement through a 4-node primitive DAG L.drive_field -> L.selection_field_ffp -> D.receive_coil -> int.temporal, with time-integrated exposure and additive Gaussian thermal/electronic noise. Recovery is posed as a non-convex inverse problem that inverts the forward operator to estimate the scene-side 3D tracer concentration. Difficulty tier delta=5 with effective condition number kappa_eff~20; calibration-level mismatch (spatial_relaxation, tracer_distribution, drive_field_harmonics) sets the accuracy floor at the Omega boundary. See the forward_model field for the closed-form imaging equation.
L-DAG
Well-posedness W
- Existence:
- true
- Uniqueness:
- true
- Stability:
- conditional
- κ:
- 400
Existence of the recovered 3D tracer concentration is guaranteed within the declared Omega bounds. Uniqueness is local rather than global (non-convex landscape); convergence depends on initialisation and priors. Stability is moderately conditioned (kappa_eff ~= 20); spatial_relaxation dominates the stability cliff; tracer_distribution and the remaining mismatch parameters contribute higher-order bias terms. Additive gaussian thermal/electronic noise sets the irreducible data-fidelity floor, while TV / wavelet-sparsity / deep priors stabilise recovery at the ill-conditioned end of Omega.
Solvability C
- Solver class:
- iterative projection (ADMM / GAP) + optimisation [Kaczmarz] | linear-operator + convex optimisation [ADMM-MPI] | linear-operator + deep neural prior [MPI-Net]
- Convergence rate q:
- 2
- Complexity:
- O(H * W * Z * log(...)) per iteration; learned variants: O(H W Z * F_theta_cost) per forward pass