Keyboard shortcuts

Press ← or → to navigate between chapters

Press ? to show this help

Press Esc to hide this help

Actual History Transfer and Signed Coefficient Extraction

Abstract

Actual History Transfer and Signed Coefficient Extraction

Definition 1.1 (edgeTilt).

Formalization. D5/S3/Estimation/TimeArrow/MarkedPoissonCoefficient.edgeTilt (✓ std3).

Source. Repository-derived.

Commentary.

The factor is the product over all marked rows j of zplus(j) when the departure is inl(m(j)) and the destination parity is 1, and zminus(j) when that departure has destination parity -1; each other factor is 1.

Definition 1.2 (sparse).

Formalization. D5/S3/Estimation/TimeArrow/MarkedPoissonCoefficient.sparse (✓ std3).

Source. Repository-derived.

Commentary.

markedSum is the finite sum of a(j) over indices for which x = inl(m(j)); all other summands are zero. This definition allows repeated marks.

Theorem 1.3 (count monomial).

Proof. Machine-checked in Lean as D5/S3/Estimation/TimeArrow/MarkedPoissonCoefficient.count_monomial (✓ std3). ∎

Source. Repository-derived.

Commentary.

countMonomial is the product over j of zplus(j)^count(e,o,m(j),1) times zminus(j)^count(e,o,m(j),-1). edgeProduct is the product over the s edges of edgeTilt at their ordered endpoints. Natural powers include zero tilts and zero counts.

Theorem 1.4 (edgeTilt eq affine).

Proof. Machine-checked in Lean as D5/S3/Estimation/TimeArrow/MarkedPoissonCoefficient.edgeTilt_eq_affine (✓ std3). ∎

Source. Repository-derived.

Commentary.

With u(j) = (zplus(j)+zminus(j))/2-1 and v(j) = (zplus(j)-zminus(j))/2, affineTilt equals 1+sparse(m,u,x)+sparse(m,v,x) chi(y). Distinct marks make at most one departure row active.

Theorem 1.5 (sparse sum).

Proof. Machine-checked in Lean as D5/S3/Estimation/TimeArrow/MarkedPoissonCoefficient.sparse_sum (✓ std3). ∎

Source. Repository-derived.

Commentary.

The left side is the sum over all x of f(x) sparse(m,a,x); the right side is the sum over all j of f(inl(m(j))) a(j). No injectivity condition is needed.

Definition 1.6 (endpointWeight).

Formalization. D5/S3/Estimation/TimeArrow/MarkedPoissonCoefficient.endpointWeight (✓ std3).

Source. Repository-derived.

Commentary.

For a finite state type X, endpointWeight(c,K,n,y) is c times the sum over all functions o : Fin(n+1) -> X ending at y of the product of K on the n consecutive ordered edges.

Theorem 1.7 (endpoint zero).

Proof. Machine-checked in Lean as D5/S3/Estimation/TimeArrow/MarkedPoissonCoefficient.endpoint_zero (✓ std3). ∎

Source. Repository-derived.

Commentary.

A length-zero path has mass c at each endpoint, including when c is zero.

Theorem 1.8 (endpoint next).

Proof. Machine-checked in Lean as D5/S3/Estimation/TimeArrow/MarkedPoissonCoefficient.endpoint_next (✓ std3). ∎

Source. Repository-derived.

Commentary.

endpointConvolution is the sum over x of endpointWeight(c,K,n,x) K(x,y). Appending the final state is a bijection of complete histories.

Theorem 1.9 (endpoint total).

Proof. Machine-checked in Lean as D5/S3/Estimation/TimeArrow/MarkedPoissonCoefficient.endpoint_total (✓ std3). ∎

Source. Repository-derived.

Commentary.

endpointSum sums endpointWeight over all final states. historySum is c times the sum of the edge-product weights of every complete length-n history.

Theorem 1.10 (tilt norms).

Proof. Machine-checked in Lean as D5/S3/Estimation/TimeArrow/MarkedPoissonCoefficient.tilt_norms (✓ std3). ∎

Source. Repository-derived.

Commentary.

tiltRadius means both coordinate vectors have norms at most R at every index. The symmetric tilt has norm at most R+1 and the antisymmetric tilt has norm at most R.

Theorem 1.11 (marked sum norm).

Proof. Machine-checked in Lean as D5/S3/Estimation/TimeArrow/MarkedPoissonCoefficient.marked_sum_norm (✓ std3). ∎

Source. Repository-derived.

Commentary.

coordinateBound means norm(a(j)) <= D for every j. One or two rows cost at most 2D in the sum norm.

Theorem 1.12 (profile sum zero).

Proof. Machine-checked in Lean as D5/S3/Estimation/TimeArrow/MarkedPoissonCoefficient.profile_sum_zero (✓ std3). ∎

Source. Repository-derived.

Commentary.

profileSum is the sum over all 2M native states of b(r,S,x). This is the zero-mean compensated profile of the finite stochastic model.

Definition 1.13 (Symmetric tilt).

Formalization. D5/S3/Estimation/TimeArrow/MarkedPoissonCoefficient.tiltU (✓ std3).

Source. Repository-derived.

Commentary.

Each marked positive departure state has two arbitrary complex tilt coordinates, one for each destination parity. The symmetric coordinate is their half-sum minus one.

Definition 1.14 (Antisymmetric tilt).

Formalization. D5/S3/Estimation/TimeArrow/MarkedPoissonCoefficient.tiltV (✓ std3).

Source. Repository-derived.

Commentary.

The antisymmetric coordinate is half the difference of the positive and negative destination tilts.

Definition 1.15 (Total-mass drift).

Formalization. D5/S3/Estimation/TimeArrow/MarkedPoissonCoefficient.driftA (✓ std3).

Source. Repository-derived.

Commentary.

The drift A averages u_j + b_j v_j over the 2M states. Here b_j is the native compensated profile at the marked positive state: b is r on positive support states, -c on the positive complement, and zero on negative states; c = rq/(M-q). Marks may lie in the support or its complement.

Definition 1.16 (Endpoint-parity drift).

Formalization. D5/S3/Estimation/TimeArrow/MarkedPoissonCoefficient.driftB (✓ std3).

Source. Repository-derived.

Commentary.

The drift B averages v_j + b_j u_j over the same state space. The compensating profile has zero total mass and vanishes on negative states.

Definition 1.17 (Actual count generating function).

Formalization. D5/S3/Estimation/TimeArrow/MarkedPoissonCoefficient.actualPGF (✓ std3).

Source. Repository-derived.

Commentary.

The sum ranges over all complete histories of T transitions, with the native uniform-start path mass. The positive and negative exponents count departures from each marked state followed by the corresponding destination parity. These counts share one history. A history is a function from Fin(T+1) to Fin(M) + Fin(M). Its mass w_T is (2M)^(-1) times the product of (1 + b(x) chi(y))/(2M) over its T edges, where chi is 1 on positive states and -1 on negative states. C_j^+ and C_j^- count edges whose departure is the positive state m(j) and whose destination chi is respectively 1 and -1. The symbol z denotes the pair (z^+, z^-). Natural powers include zero tilt coordinates and use the convention zero to the zeroth power equals one.

Definition 1.18 (Forward endpoint state).

Formalization. D5/S3/Estimation/TimeArrow/MarkedPoissonCoefficient.forwardState (✓ std3).

Source. Repository-derived.

Commentary.

The row-coordinate state begins at (1,0). At each step its first coordinate becomes (1+A)x+A y and its second becomes B x+B y. The coordinates are the total and parity coefficients of the actual tilted endpoint density.

Definition 1.19 (Forward transfer matrix).

Formalization. D5/S3/Estimation/TimeArrow/MarkedPoissonCoefficient.forwardMatrix (✓ std3).

Source. Repository-derived.

Commentary.

The entries, listed in row order, are 1+A, B, A, B. At zero drift this is the projection onto the first coordinate.

Theorem 1.20 (Actual path transfer identity).

Proof. Machine-checked in Lean as D5/S3/Estimation/TimeArrow/MarkedPoissonCoefficient.actual_marked_path_transfer (✓ std3). ∎

Source. Repository-derived.

Commentary.

For every natural T, including zero, and every complex tilt, actualPGF equals both the first coordinate of forwardState and the (0,0) entry of the T-th power of forwardMatrix. A and B are the compensated drifts of the same fixed support and marked rows. The proof sums actual complete-history weights through their endpoint density. No bound on the tilts and no restriction to one or two rows is required for this exact identity.

Theorem 1.21 (finite count poisson relative).

Proof. Machine-checked in Lean as D5/S3/Estimation/TimeArrow/MarkedPoissonCoefficient.finite_count_poisson_relative (✓ std3). ∎

Source. Repository-derived.

Commentary.

Omega is an arbitrary finite history carrier. w is an arbitrary real weight; nonnegativity is not required. cp and cm are natural count vectors. positiveMeanLowerBounds means that each muplus(j) and muminus(j) is positive and at least kappa L/2. coordinateCountBound means every prescribed coordinate is at most Czero L. tiltRadius bounds both complex tilt vectors coordinatewise. countPGF is the weighted sum of the count monomials; poissonPGF is exp(sum_j(muplus(j)(zp(j)-1)+muminus(j)(zm(j)-1))). signedPoissonScale is exp of the real part of that same exponent. P sums w over the simultaneous exact-count event. Q is the product over both signs and all j of exp(-mu) mu^n/n!. The displayed constant uses pi, the circle constant. The proof extracts coefficients on a product torus at positive radii (n+1)/mu, then applies the factorial estimate including n=0. It permits zero tilts and rare original point masses.

References