The remaining blocks are , , , and , repeated for their components. Nonzero residuals add lower-order forces but no omitted derivative Hessian: each nonclock residual is affine in derivatives with algebraic coefficients.
For finite , positive smooth constitutive coefficients and regular future flow/frame coordinates, each is Lorentzian and its ray cone lies in the ordinary unit cone. Therefore any inertial laboratory time has , and
This remains true when the canonical spatial energy matrix is indefinite. In holonomic variables , define and . The exact principal equations can be augmented by curls:
A smooth simultaneous symmetrizer is the following quadratic form on tangent increments :
It is not the Jacobian of a nonlinear change to convected velocities. That distinction matters because depends on the first jet. At a frozen state the corresponding wave blocks have symmetric matrices and positive time form . Pullback gives the displayed symmetrizer for every direction at once.
For , exact differentiation gives
symmetrizes every , so this homogeneous constraint system preserves zero curl. Then remains zero as well. The regular algebraic charts and auxiliary reconstruction preserve the remaining constraints. No global phase coordinate or vanishing carrier curvature was assumed.
Every fixed compatible compact datum with , , integer , lying in this regular positive region therefore has a positive data-dependent local existence time. Its norm and finite gradients need not be small. On a finite collar the compact initial first-jet image provides positive bounds for the symmetrizer. Apply the local symmetric-hyperbolic theorem there. Alternatively extend the matrices after symmetrization, blending to the identity and to zero; positivity, symmetry and the cone inequalities survive. Local uniqueness glues to the exact rational exterior. Overlapping regular target charts may be treated locally and glued on compatible Euler solutions.
The solution has , , , with the usual lower-Sobolev-norm continuous dependence. Reconstructed and generally have only perturbation regularity because depends on first derivatives. There are no independently prescribed density velocity data.
This theorem includes each fixed regular compact tail competitor, but
does not supply evolution toward it. No uniform lifespan in tail radius,
vacuum crossing, infinite-carrier limit, instability, decay or nonlinear
stability follows. Both phase-edge choices and both smooth positive
coefficient branches obey the proof at every maintained depth. The source
compact-large-data-symbol/report.md and independent 25-check review give
the complete action, constraint proof and external PDE theorem attribution.
The 431 author checks are supplementary small-matrix controls, not numerical
solutions of all full-carrier actions.
Smooth Density Relaxation With All Retained Charges
The two-region calculation has a smooth spatial counterpart that retains the actual joining layer. Fix rational support positions, rest independent