Chapter 2 Symbols, Terms & Units


I. Abstract & Scope
This chapter unifies the volume’s symbols, terminology, and SI unit conventions. It fixes notation and dimensional rules for orientation quantities (n_hat, f_orient(n_hat,r,t), Q_ij) and the oriented-tension family (T_fil/T_fil_vec/T_fil_ij). All equations and symbols use English notation wrapped in backticks, with dimensional closure mandatory. If time-of-arrival (ToA) appears, both forms must be recorded in parallel with explicit path gamma(ell) and measure d ell.

II. Dependencies & References

III. Normative Anchors (added in this chapter, P80-/M80-)

IV. Body Structure


I. Terminology Domain & Naming Rules


II. Notation & Layout Rules


III. Units & Dimensional Rules (minimum set)


IV. ToA-Related Fields (iff present)

  1. Recorded items: T_arr^A, T_arr^B, delta_form, gamma(ell), d ell, n_eff(ν,r), c_ref.
  2. Expressions & units: T_arr in s; n_eff in 1; d ell in m.
  3. Dataset-card interface: in DatasetCard.columns, ToA fields MUST include both forms and delta_form; integrals MUST provide {path, measure}.

V. Validation, Criteria & Contrasts

  1. Positive criteria:
    • Every numeric column carries unit/dim; UnitsAudit.log passes dimensional closure.
    • Orientation relations satisfy ∫_{S^2} f_orient dΩ = 1.
    • If ToA appears, both forms with delta_form and {gamma(ell), d ell} are present.
  2. Negative criteria:
    • Mixing T_fil with T_trans; conflating n with n_eff.
    • Phi(E) missing sr or energy dimension.
    • Only one T_arr form provided without the counterpart and path/measure.
  3. Contrasts:
    • {with/without sr} audit for Phi(E).
    • {normalized / unnormalized} f_orient effects on Q_ij.
    • {ToA Form A, Form B, A+B} audit differences in the same dataset card.

VI. Deliverables & Figure List

  1. Deliverables: Glossary.md (terms & do-not-confuse list), SymbolRegistry.csv (central symbols—units—dimensions), UnitsAudit.log (from M80-12), ToA.dualform.log (if applicable).
  2. Tables/Figures (this chapter):
    • Tab. 2-1 Minimal symbol table (Orientation / Tension / Coupling / Transport).
    • Tab. 2-2 Do-not-confuse list.
    • Tab. 2-3 Key observables with units & dimensions (Phi(E), N(E), T_fil_ij, D_Q, tau_relax).
    • Tab. 2-4 Suffixes & reserved words.
    • Tab. 2-5 DatasetCard ToA field template (if applicable).

Tab. 2-1 Minimal Symbol Table

Symbol

Meaning

Unit (SI)

Dim

See

n_hat

unit orientation vector

1

1

Ch.3

f_orient(n_hat,r,t)

orientation distribution function

1

1

Ch.3

Q_ij

order tensor

1

1

Ch.3

T_fil / T_fil_vec / T_fil_ij

oriented tension (scalar/vector/tensor)

Pa

M L^-1 T^-2

Ch.4

W_orient

orientation energy density

J·m^-3

M L^-1 T^-2

Ch.4/7

A_cpl

coupling rate

s^-1

T^-1

Ch.6

D_Q

order-parameter diffusivity

m^2·s^-1

L^2 T^-1

Ch.6

u_vec

flow speed

m·s^-1

L T^-1

Ch.6

Phi(E)

differential flux

m^-2·s^-1·sr^-1·eV^-1

L^-2 T^-1 Ω^-1 E^-1

Ch.7

tau_relax

orientation relaxation time

s

T

Ch.4/5


Tab. 2-2 Do-Not-Confuse List

Conflict

Correct usage

Forbidden usage

Rule

tension vs transmittance

T_fil

T_trans

never use T_trans for tension

number density vs effective index

n

n_eff

distinct physics; never interchangeable

Lorentz factor vs path

Gamma

gamma(ell)

case-sensitive; gamma(ell) is for paths

order tensor vs injection normalization

Q_ij

Q0_Z

scope/rename to avoid ambiguity


Tab. 2-3 Key Observables (Units & Dimensions)

Quantity

Unit

Dim

Audit focus

Phi(E)

m^-2·s^-1·sr^-1·eV^-1

L^-2 T^-1 Ω^-1 E^-1

must include sr and E^-1

T_fil_ij

Pa

M L^-1 T^-2

same as stress tensor

D_Q

m^2·s^-1

L^2 T^-1

diffusivity

tau_relax

s

T

time quantity

N(E)

1

1

pure count

dN/dE

eV^-1

E^-1

inverse energy


Tab. 2-4 Suffixes & Reserved Words

Class

Convention

Example

vector/field

_vec / _fld

u_vec, B_vec

reference-frame tag

(_flow/_sheet/_shear)

Q_ij(flow)

path & measure

gamma(ell), d ell

∫_{gamma(ell)} (…) d ell

ToA markers

T_arr^A, T_arr^B, delta_form

record in parallel


Tab. 2-5 DatasetCard ToA Field Template (if applicable)

Field

Unit

Dim

Note

T_arr^A

s

T

constant-factored form

T_arr^B

s

T

general form

delta_form

selected form flag

integrals.path

gamma(ell)

integrals.measure

m

L

d ell