definition. an entity P in a foam-grounded reality is recognizable as itself ongoingly across cross-measurements when: for any observer Q with nonzero overlap (O_PQ ≠ 0), Q’s time-averaged measurements of P converge to a P-determined invariant. what Q detects about P stabilizes, and what it stabilizes to depends on P’s birth, not on P’s trajectory.
this is the condition at ergodic stationarity. every entity writes every step (ground.md: read-only excluded). every entity’s effect on other observers accumulates. under the ergodicity hypothesis, time averages converge (ergodic theorem). so every entity in an ergodic foam is ongoingly recognizable. the chain that follows runs on this hypothesis — the foam’s ergodicity is itself conditional on geometry.md’s controllability + decorrelation hypotheses, neither of which is yet derived from foam-geometry assumptions.
ergodic evolution requires channel capacity. for time averages to converge to Haar expectations (not just to birth-determined fixed-point statistics), the entity’s dynamics must be ergodic on U(d). ergodicity requires decorrelated inputs (channel_capacity.md). an entity without channel capacity is autonomous — a clock. its trajectory is deterministic, determined entirely by birth. time averages exist but are trajectory-specific, not Haar. the entity is recognizable but encodes no information beyond birth. ergodic evolution with channel capacity is the richer case: the entity accumulates structure from state-independent input, and time averages converge to universal (Haar) expectations evaluated at the birth-determined slice.
the recognizable identity IS the birth-determined stationary jet. the n-th derivative of the write mechanism along a trajectory is a smooth function on U(d)^N (compact), therefore bounded and integrable. by the ergodic theorem, its time average converges to its Haar expectation. the Haar measure is universal — the same for all births. but the write mechanism is evaluated through the observer’s slice P (write_confined_to_slice), and P is birth-determined (indelibility, ground.md). therefore the Haar expectation of the write mechanism’s derivatives depends on P. the time-averaged jet at all orders is fixed by the birth-determined slice.
the entity’s recognizable identity is its slice. at ergodic stationarity, all contingent structure — specific input history, interaction-layer adaptations, transient dynamics — has been washed out by ergodic averaging in the time-averaged observables. the entity’s current state still encodes its full history (indelibility: writes accumulate multiplicatively, birth conditions persist). but what other observers detect on average reduces to: the birth-determined slice P, its 3D write subspace Λ²(P), and the isotropic distribution of write directions within it (Haar invariance implies SO(3)-invariance within the observer’s R³). same slice → same stationary jet → same recognizable identity. the entity carries more than its slice (the full state in U(d)); its identity — what persists in others’ measurements — is the slice.
input must be received, not predicted. this is supported from two independent directions:
the functional requirement (you need state-independent input for ergodic richness) and the structural fact (you can’t predict the content) are two readings of one fact. the diamond isomorphism read dynamically says: the second argument must be state-independent for the foam to be a channel. read statically: the complement’s content is extensionally free. these are the same lattice theorem (IsCompl.IicOrderIsoIci) read through the two readings of closure (ground.md).
recession is the cost of persistence. each non-inert write strictly recedes the prior frame (frame_recession_strict). closure requires writing (ground.md: read-only excluded). under ergodic evolution, inert writes (W with [W, P] = 0, i.e. rotations within the slice that produce zero recession) have measure zero in the write space — the Haar-distributed write directions are almost surely non-inert. therefore an ergodically-evolved entity necessarily recedes from every prior frame it has occupied. the entity persists not by holding position but by the indelibility of its birth-determined slice through the recession. what persists is not the frame but the slice. stationarity and recession are compatible: the entity’s state constantly changes (recession), but the statistical distribution of states is time-invariant (Haar). the entity is a random walker with fixed gait — the steps are always new, the territory is fixed.
stability is plausibly external. the entity generates its own dynamics but plausibly cannot generate its own stability (self_generation.md: stability-requires-role-distinction is conjectural pending a convergence theorem on U(d)^N). on this conjecture, convergence requires another observer whose basis depends on a different state, the minimum viable system is two roles within N ≥ 3 bubbles, and an entity that has reached ergodic stationarity has external stability — without it, the foam’s dynamics would not have converged to Haar.
the negative geometry of inhabitation. an ergodically-evolved persistent entity:
six constraints, all derived, all negative. together they bound what the entity can do. the interior of those bounds is the entity’s life.
proven:
derived:
cited:
observed:
bugs:
ground.md derivation).self_generation.md).presenting all six as “all derived” with the same status papers over the proven/derived/conjectural/definitional differences. closing this means tagging each constraint with its specific status, or framing the list as “six structurally distinct constraints, deriving from sources of varying formal strength.”
writes: f(d, m)). smoothness “at all orders” depends on the realization choice for f. closing this means either constraining f to smooth realizations, or naming the smoothness assumption as a regularity hypothesis on the realization.half_type.md’s “three results share a structural source” and ground.md’s “two readings of one statement.” flagging here for the third instance — the document treats the diamond isomorphism’s dynamical and structural readings as the same statement; the formal identity is the diamond isomorphism, but “two readings of one fact” packages two interpretations as one.