For real variables p , s , a , b , c p,s,a,b,c p , s , a , b , c , set
K = a 2 + b 2 + c 2 − 2 ( a b + b c + c a ) , S = p 2 + s 2 , C = S + K . K=a^2+b^2+c^2-2(ab+bc+ca),\qquad S=p^2+s^2,\qquad C=S+K. K = a 2 + b 2 + c 2 − 2 ( ab + b c + c a ) , S = p 2 + s 2 , C = S + K .
The shear components and wall rates are
P = K p − 2 a 2 + b 2 + c 2 + a b − 2 b c + a c , P=Kp-2a^2+b^2+c^2+ab-2bc+ac, P = K p − 2 a 2 + b 2 + c 2 + ab − 2 b c + a c ,
Q = K s + 3 ( − b 2 + c 2 + a b − a c ) , Q=Ks+\sqrt{3}(-b^2+c^2+ab-ac), Q = K s + 3 ( − b 2 + c 2 + ab − a c ) ,
r 1 = − S + 2 p , r 2 = − S − p + 3 s , r 3 = − S − p − 3 s . r_1=-S+2p,\qquad r_2=-S-p+\sqrt{3}s,\qquad r_3=-S-p-\sqrt{3}s. r 1 = − S + 2 p , r 2 = − S − p + 3 s , r 3 = − S − p − 3 s .
These functions define the normalized vacuum Bianchi IX vector field
( P , Q , r 1 a , r 2 b , r 3 c ) (P,Q,r_1a,r_2b,r_3c) ( P , Q , r 1 a , r 2 b , r 3 c ) .
For y = ( m , u , v , w ) ∈ R 4 y=(m,u,v,w)\in\mathbb R^4 y = ( m , u , v , w ) ∈ R 4 , define
K ( u , v , w ) = u 2 + v 2 + w 2 − 2 ( u v + v w + w u ) , κ = u ( v + w − u ) , K(u,v,w)=u^2+v^2+w^2-2(uv+vw+wu),\qquad \kappa=u(v+w-u), K ( u , v , w ) = u 2 + v 2 + w 2 − 2 ( uv + v w + w u ) , κ = u ( v + w − u ) ,
F m = − v 2 + w 2 + u ( v − w ) − m κ , F u = 1 2 ( 1 − m 2 − ( v − w ) 2 + u 2 ) u , F_m=-v^2+w^2+u(v-w)-m\kappa,\qquad
F_u=\tfrac12(1-m^2-(v-w)^2+u^2)u, F m = − v 2 + w 2 + u ( v − w ) − mκ , F u = 2 1 ( 1 − m 2 − ( v − w ) 2 + u 2 ) u ,
F v = ( m − 1 − κ ) v , F w = ( − m − 1 − κ ) w , F = ( F m , F u , F v , F w ) , F_v=(m-1-\kappa)v,\qquad F_w=(-m-1-\kappa)w,\qquad
F=(F_m,F_u,F_v,F_w), F v = ( m − 1 − κ ) v , F w = ( − m − 1 − κ ) w , F = ( F m , F u , F v , F w ) ,
and E ( m , v ) = ( m − 1 ) 2 + v 2 E(m,v)=(m-1)^2+v^2 E ( m , v ) = ( m − 1 ) 2 + v 2 .
For x = ( p , s , a , b , c ) x=(p,s,a,b,c) x = ( p , s , a , b , c ) , put
ψ ( p , z ) = 3 z 1 + p , Π ( x ) = ( ψ ( p , s ) , ψ ( p , a ) , ψ ( p , b ) , ψ ( p , c ) ) . \psi(p,z)=\frac{\sqrt3\,z}{1+p},\qquad
\Pi(x)=(\psi(p,s),\psi(p,a),\psi(p,b),\psi(p,c)). ψ ( p , z ) = 1 + p 3 z , Π ( x ) = ( ψ ( p , s ) , ψ ( p , a ) , ψ ( p , b ) , ψ ( p , c )) .
For y = ( m , u , v , w ) y=(m,u,v,w) y = ( m , u , v , w ) , set D ( y ) = 3 + m 2 + K ( u , v , w ) D(y)=3+m^2+K(u,v,w) D ( y ) = 3 + m 2 + K ( u , v , w ) and
Ξ A ( y ) = ( A − 1 , A m 3 , A u 3 , A v 3 , A w 3 ) , Ξ ( y ) = Ξ 6 / D ( y ) ( y ) . \Xi_A(y)=\left(A-1,\frac{Am}{\sqrt3},\frac{Au}{\sqrt3},
\frac{Av}{\sqrt3},\frac{Aw}{\sqrt3}\right),\qquad
\Xi(y)=\Xi_{6/D(y)}(y). Ξ A ( y ) = ( A − 1 , 3 A m , 3 A u , 3 A v , 3 A w ) , Ξ ( y ) = Ξ 6/ D ( y ) ( y ) .
Write N ( x ) = ( P , Q , r 1 a , r 2 b , r 3 c ) N(x)=(P,Q,r_1a,r_2b,r_3c) N ( x ) = ( P , Q , r 1 a , r 2 b , r 3 c ) for the normalized vector field
and C ( x ) = C ( p , s , a , b , c ) \mathcal C(x)=C(p,s,a,b,c) C ( x ) = C ( p , s , a , b , c ) for its constraint.
The normalized and projective state spaces are R 5 \mathbb R^5 R 5 and R 4 \mathbb R^4 R 4
with their finite-product norms. The maps Π , Ξ , D , F \Pi,\Xi,D,F Π , Ξ , D , F act on these state spaces.
Define the core radius, angle, and clock factor by
r ( m , v ) = ( m − 1 ) 2 + v 2 , θ ( m , v ) = arsinh 1 − m v , d ( r , u , w ) = 1 − ( u − w ) 2 r 2 . r(m,v)=\sqrt{(m-1)^2+v^2},\qquad
\theta(m,v)=\operatorname{arsinh}\frac{1-m}{v},\qquad
d(r,u,w)=1-\frac{(u-w)^2}{r^2}. r ( m , v ) = ( m − 1 ) 2 + v 2 , θ ( m , v ) = arsinh v 1 − m , d ( r , u , w ) = 1 − r 2 ( u − w ) 2 .
For y = ( m , u , v , w ) y=(m,u,v,w) y = ( m , u , v , w ) , write r y = r ( m , v ) r_y=r(m,v) r y = r ( m , v ) , θ y = θ ( m , v ) \theta_y=\theta(m,v) θ y = θ ( m , v ) ,
and d y = d ( r y , u , w ) d_y=d(r_y,u,w) d y = d ( r y , u , w ) . All quotients use the total convention x / 0 = 0 x/0=0 x /0 = 0 .
The core state space is R 3 \mathbb R^3 R 3 with coordinates Y = ( r , u , p ) Y=(r,u,p) Y = ( r , u , p ) .
Define
η ( m , u , v , w ) = ( r ( m , v ) , u , v w ) , ι z ( r , u , p ) = ( 1 − r tanh z , u , r cosh z , p r / cosh z ) . \eta(m,u,v,w)=(r(m,v),u,vw),\qquad
\iota_z(r,u,p)=\left(1-r\tanh z,u,\frac r{\cosh z},
\frac p{r/\cosh z}\right). η ( m , u , v , w ) = ( r ( m , v ) , u , v w ) , ι z ( r , u , p ) = ( 1 − r tanh z , u , cosh z r , r / cosh z p ) .
For fixed ( z , Y ) (z,Y) ( z , Y ) put v = r / cosh z v=r/\cosh z v = r / cosh z , w = p / v w=p/v w = p / v , d = d ( r , u , w ) d=d(r,u,w) d = d ( r , u , w ) , and define
V ( z , Y ) = ( − κ ( u , v , w ) − tanh z ( u − w ) 2 / r d , u [ − r / 2 + tanh z + w / cosh z + ( u 2 − w 2 ) / ( 2 r ) ] d , − 2 p ( 1 + κ ( u , v , w ) ) r d ) . \mathcal V(z,Y)=\left(
\frac{-\kappa(u,v,w)-\tanh z\,(u-w)^2/r}{d},\quad
\frac{u[-r/2+\tanh z+w/\cosh z+(u^2-w^2)/(2r)]}{d},\quad
\frac{-2p(1+\kappa(u,v,w))}{rd}\right). V ( z , Y ) = ( d − κ ( u , v , w ) − tanh z ( u − w ) 2 / r , d u [ − r /2 + tanh z + w / cosh z + ( u 2 − w 2 ) / ( 2 r )] , r d − 2 p ( 1 + κ ( u , v , w )) ) .
For real k k k , put ε k = 1 / ( 10000 k ) \varepsilon_k=1/(10000k) ε k = 1/ ( 10000 k ) and define
K k = { ( m , u , v , w ) : ∣ E ( m , v ) − k 2 ∣ ≤ 1 / 8 , v ≥ 1 , 0 ≤ u ≤ ε k , 0 ≤ v w ≤ ε k } . \mathcal K_k=\{(m,u,v,w): |E(m,v)-k^2|\leq1/8,\quad v\geq1,
\quad0\leq u\leq\varepsilon_k,\quad0\leq vw\leq\varepsilon_k\}. K k = {( m , u , v , w ) : ∣ E ( m , v ) − k 2 ∣ ≤ 1/8 , v ≥ 1 , 0 ≤ u ≤ ε k , 0 ≤ v w ≤ ε k } .
Write X = R 5 X=\mathbb R^5 X = R 5 , Y = R 4 Y=\mathbb R^4 Y = R 4 , and let α x , t 0 \alpha_{x,t_0} α x , t 0 be the
maximal solution of α ′ = N ( α ) \alpha'=N(\alpha) α ′ = N ( α ) with initial value x x x at t 0 t_0 t 0
and domain I max ( x , t 0 ) I_{\max}(x,t_0) I m a x ( x , t 0 ) . Put
J x , t 0 ( t ) = d x α x , t 0 ( t ) , Ψ t 0 ( y , t ) = Π ( α Ξ ( y ) , t 0 ( t ) ) , J_{x,t_0}(t)=d_x\alpha_{x,t_0}(t),\qquad
\Psi_{t_0}(y,t)=\Pi(\alpha_{\Xi(y),t_0}(t)), J x , t 0 ( t ) = d x α x , t 0 ( t ) , Ψ t 0 ( y , t ) = Π ( α Ξ ( y ) , t 0 ( t )) ,
J y , t 0 ( t ) = d Π α Ξ ( y ) , t 0 ( t ) ∘ J Ξ ( y ) , t 0 ( t ) ∘ d Ξ y . \mathcal J_{y,t_0}(t)=d\Pi_{\alpha_{\Xi(y),t_0}(t)}
\circ J_{\Xi(y),t_0}(t)\circ d\Xi_y. J y , t 0 ( t ) = d Π α Ξ ( y ) , t 0 ( t ) ∘ J Ξ ( y ) , t 0 ( t ) ∘ d Ξ y .
Write G ( y ) = 6 F ( y ) / D ( y ) G(y)=6F(y)/D(y) G ( y ) = 6 F ( y ) / D ( y ) , λ ( y ) = 6 r y d y / D ( y ) \lambda(y)=6r_yd_y/D(y) λ ( y ) = 6 r y d y / D ( y ) , and
S k ( R , U , P ) = ( R , k U , P ) S_k(R,U,P)=(R,kU,P) S k ( R , U , P ) = ( R , k U , P ) . Define
P y ξ = d η y ξ − d θ y ξ V ( θ y , η ( y ) ) , W y , t 0 , w ( t ) = P Ψ t 0 ( y , t ) ( J y , t 0 ( t ) w ) . \mathcal P_y\xi=d\eta_y\xi-d\theta_y\xi\,\mathcal V(\theta_y,\eta(y)),
\qquad \mathcal W_{y,t_0,w}(t)=
\mathcal P_{\Psi_{t_0}(y,t)}(\mathcal J_{y,t_0}(t)w). P y ξ = d η y ξ − d θ y ξ V ( θ y , η ( y )) , W y , t 0 , w ( t ) = P Ψ t 0 ( y , t ) ( J y , t 0 ( t ) w ) .
The entrance parametrization and radial exit factor are
e ( k , u , w ) = ( 1 + k 2 − 1 , u , 1 , w ) , e(k,u,w)=(1+\sqrt{k^2-1},u,1,w), e ( k , u , w ) = ( 1 + k 2 − 1 , u , 1 , w ) ,
f y = V ( θ y , η ( y ) ) 0 , c y = − tanh θ y , h y = c y + f y / r y , ρ y = c y / h y . f_y=\mathcal V(\theta_y,\eta(y))_0,\qquad c_y=-\tanh\theta_y,
\qquad h_y=c_y+f_y/r_y,\qquad \rho_y=c_y/h_y. f y = V ( θ y , η ( y ) ) 0 , c y = − tanh θ y , h y = c y + f y / r y , ρ y = c y / h y .
For projective initial data y y y , put
A y , t 0 ( t ) = 1 + ( α Ξ ( y ) , t 0 ( t ) ) 0 . A_{y,t_0}(t)=1+(\alpha_{\Xi(y),t_0}(t))_0. A y , t 0 ( t ) = 1 + ( α Ξ ( y ) , t 0 ( t ) ) 0 .
Coordinates of three-vectors are indexed by 0 , 1 , 2 0,1,2 0 , 1 , 2 ; projective
coordinates are indexed by m , u , v , w m,u,v,w m , u , v , w .
For Y ∈ R 3 Y\in\mathbb R^3 Y ∈ R 3 , put x Y = Ξ ( e ( Y ) ) x_Y=\Xi(e(Y)) x Y = Ξ ( e ( Y )) ,
β Y ( t ) = Ψ 0 ( e ( Y ) , t ) \beta_Y(t)=\Psi_0(e(Y),t) β Y ( t ) = Ψ 0 ( e ( Y ) , t ) , and
H Y = { t > 0 : t ∈ I max ( x Y , 0 ) , ( β Y ( t ) ) v = 1 } , T ( Y ) = inf H Y , F ( Y ) = η ( β Y ( T ( Y ) ) ) . H_Y=\{t>0:t\in I_{\max}(x_Y,0),\ (\beta_Y(t))_v=1\},
\qquad T(Y)=\inf H_Y,\qquad F(Y)=\eta(\beta_Y(T(Y))). H Y = { t > 0 : t ∈ I m a x ( x Y , 0 ) , ( β Y ( t ) ) v = 1 } , T ( Y ) = inf H Y , F ( Y ) = η ( β Y ( T ( Y ))) .
The infimum uses the total real-order convention. Write Valid ( Y ) \operatorname{Valid}(Y) Valid ( Y )
when T ( Y ) T(Y) T ( Y ) is the least element of H Y H_Y H Y , every t ∈ [ 0 , T ( Y ) ] t\in[0,T(Y)] t ∈ [ 0 , T ( Y )] lies in
I max ( x Y , 0 ) I_{\max}(x_Y,0) I m a x ( x Y , 0 ) with A e ( Y ) , 0 ( t ) > 0 A_{e(Y),0}(t)>0 A e ( Y ) , 0 ( t ) > 0 , the active wall is strictly
above one for 0 < t < T ( Y ) 0<t<T(Y) 0 < t < T ( Y ) , and
d g α x Y , 0 ( T ( Y ) ) N ( α x Y , 0 ( T ( Y ) ) ) < 0 , g ( x ) = ( Π ( x ) ) v . dg_{\alpha_{x_Y,0}(T(Y))}N(\alpha_{x_Y,0}(T(Y)))<0,
\qquad g(x)=(\Pi(x))_v. d g α x Y , 0 ( T ( Y )) N ( α x Y , 0 ( T ( Y ))) < 0 , g ( x ) = ( Π ( x ) ) v .
All vector and operator norms below use the finite-product supremum norm.
For real variables p , s , a , b , c p,s,a,b,c p , s , a , b , c , set
K = a 2 + b 2 + c 2 − 2 ( a b + b c + c a ) , S = p 2 + s 2 , C = S + K . K=a^2+b^2+c^2-2(ab+bc+ca),\qquad S=p^2+s^2,\qquad C=S+K. K = a 2 + b 2 + c 2 − 2 ( ab + b c + c a ) , S = p 2 + s 2 , C = S + K .
The shear components and wall rates are
P = K p − 2 a 2 + b 2 + c 2 + a b − 2 b c + a c , P=Kp-2a^2+b^2+c^2+ab-2bc+ac, P = K p − 2 a 2 + b 2 + c 2 + ab − 2 b c + a c ,
Q = K s + 3 ( − b 2 + c 2 + a b − a c ) , Q=Ks+\sqrt{3}(-b^2+c^2+ab-ac), Q = K s + 3 ( − b 2 + c 2 + ab − a c ) ,
r 1 = − S + 2 p , r 2 = − S − p + 3 s , r 3 = − S − p − 3 s . r_1=-S+2p,\qquad r_2=-S-p+\sqrt{3}s,\qquad r_3=-S-p-\sqrt{3}s. r 1 = − S + 2 p , r 2 = − S − p + 3 s , r 3 = − S − p − 3 s .
These functions define the normalized vacuum Bianchi IX vector field
( P , Q , r 1 a , r 2 b , r 3 c ) (P,Q,r_1a,r_2b,r_3c) ( P , Q , r 1 a , r 2 b , r 3 c ) .
For y = ( m , u , v , w ) ∈ R 4 y=(m,u,v,w)\in\mathbb R^4 y = ( m , u , v , w ) ∈ R 4 , define
K ( u , v , w ) = u 2 + v 2 + w 2 − 2 ( u v + v w + w u ) , κ = u ( v + w − u ) , K(u,v,w)=u^2+v^2+w^2-2(uv+vw+wu),\qquad \kappa=u(v+w-u), K ( u , v , w ) = u 2 + v 2 + w 2 − 2 ( uv + v w + w u ) , κ = u ( v + w − u ) ,
F m = − v 2 + w 2 + u ( v − w ) − m κ , F u = 1 2 ( 1 − m 2 − ( v − w ) 2 + u 2 ) u , F_m=-v^2+w^2+u(v-w)-m\kappa,\qquad
F_u=\tfrac12(1-m^2-(v-w)^2+u^2)u, F m = − v 2 + w 2 + u ( v − w ) − mκ , F u = 2 1 ( 1 − m 2 − ( v − w ) 2 + u 2 ) u ,
F v = ( m − 1 − κ ) v , F w = ( − m − 1 − κ ) w , F = ( F m , F u , F v , F w ) , F_v=(m-1-\kappa)v,\qquad F_w=(-m-1-\kappa)w,\qquad
F=(F_m,F_u,F_v,F_w), F v = ( m − 1 − κ ) v , F w = ( − m − 1 − κ ) w , F = ( F m , F u , F v , F w ) ,
and E ( m , v ) = ( m − 1 ) 2 + v 2 E(m,v)=(m-1)^2+v^2 E ( m , v ) = ( m − 1 ) 2 + v 2 .
For x = ( p , s , a , b , c ) x=(p,s,a,b,c) x = ( p , s , a , b , c ) , put
ψ ( p , z ) = 3 z 1 + p , Π ( x ) = ( ψ ( p , s ) , ψ ( p , a ) , ψ ( p , b ) , ψ ( p , c ) ) . \psi(p,z)=\frac{\sqrt3\,z}{1+p},\qquad
\Pi(x)=(\psi(p,s),\psi(p,a),\psi(p,b),\psi(p,c)). ψ ( p , z ) = 1 + p 3 z , Π ( x ) = ( ψ ( p , s ) , ψ ( p , a ) , ψ ( p , b ) , ψ ( p , c )) .
For y = ( m , u , v , w ) y=(m,u,v,w) y = ( m , u , v , w ) , set D ( y ) = 3 + m 2 + K ( u , v , w ) D(y)=3+m^2+K(u,v,w) D ( y ) = 3 + m 2 + K ( u , v , w ) and
Ξ A ( y ) = ( A − 1 , A m 3 , A u 3 , A v 3 , A w 3 ) , Ξ ( y ) = Ξ 6 / D ( y ) ( y ) . \Xi_A(y)=\left(A-1,\frac{Am}{\sqrt3},\frac{Au}{\sqrt3},
\frac{Av}{\sqrt3},\frac{Aw}{\sqrt3}\right),\qquad
\Xi(y)=\Xi_{6/D(y)}(y). Ξ A ( y ) = ( A − 1 , 3 A m , 3 A u , 3 A v , 3 A w ) , Ξ ( y ) = Ξ 6/ D ( y ) ( y ) .
Write N ( x ) = ( P , Q , r 1 a , r 2 b , r 3 c ) N(x)=(P,Q,r_1a,r_2b,r_3c) N ( x ) = ( P , Q , r 1 a , r 2 b , r 3 c ) for the normalized vector field
and C ( x ) = C ( p , s , a , b , c ) \mathcal C(x)=C(p,s,a,b,c) C ( x ) = C ( p , s , a , b , c ) for its constraint.
The normalized and projective state spaces are R 5 \mathbb R^5 R 5 and R 4 \mathbb R^4 R 4
with their finite-product norms. The maps Π , Ξ , D , F \Pi,\Xi,D,F Π , Ξ , D , F act on these state spaces.
The projective vector field in normalized time is
G ( y ) = 6 D ( y ) F ( y ) . G(y)=\frac6{D(y)}F(y). G ( y ) = D ( y ) 6 F ( y ) .
Write X = R 5 X=\mathbb R^5 X = R 5 , Y = R 4 Y=\mathbb R^4 Y = R 4 , and let α x , t 0 \alpha_{x,t_0} α x , t 0 be the
maximal solution of α ′ = N ( α ) \alpha'=N(\alpha) α ′ = N ( α ) with initial value x x x at t 0 t_0 t 0
and domain I max ( x , t 0 ) I_{\max}(x,t_0) I m a x ( x , t 0 ) . Put
J x , t 0 ( t ) = d x α x , t 0 ( t ) , Ψ t 0 ( y , t ) = Π ( α Ξ ( y ) , t 0 ( t ) ) , J_{x,t_0}(t)=d_x\alpha_{x,t_0}(t),\qquad
\Psi_{t_0}(y,t)=\Pi(\alpha_{\Xi(y),t_0}(t)), J x , t 0 ( t ) = d x α x , t 0 ( t ) , Ψ t 0 ( y , t ) = Π ( α Ξ ( y ) , t 0 ( t )) ,
J y , t 0 ( t ) = d Π α Ξ ( y ) , t 0 ( t ) ∘ J Ξ ( y ) , t 0 ( t ) ∘ d Ξ y . \mathcal J_{y,t_0}(t)=d\Pi_{\alpha_{\Xi(y),t_0}(t)}
\circ J_{\Xi(y),t_0}(t)\circ d\Xi_y. J y , t 0 ( t ) = d Π α Ξ ( y ) , t 0 ( t ) ∘ J Ξ ( y ) , t 0 ( t ) ∘ d Ξ y .
Put c = u ( v + w − u ) c=u(v+w-u) c = u ( v + w − u ) , s ( m , u , v , w ) = m − 1 − c s(m,u,v,w)=m-1-c s ( m , u , v , w ) = m − 1 − c ,
b ( m , u , v , w ) = ( 1 − m 2 − ( v − w ) 2 + u 2 ) / 2 b(m,u,v,w)=(1-m^2-(v-w)^2+u^2)/2 b ( m , u , v , w ) = ( 1 − m 2 − ( v − w ) 2 + u 2 ) /2 ,
D ( m , u , v , w ) = 3 + m 2 + K ( u , v , w ) D(m,u,v,w)=3+m^2+K(u,v,w) D ( m , u , v , w ) = 3 + m 2 + K ( u , v , w ) , and r ( m , v ) = ( m − 1 ) 2 + v 2 r(m,v)=\sqrt{(m-1)^2+v^2} r ( m , v ) = ( m − 1 ) 2 + v 2 .
Define
C μ = { ( m , u , v , w ) : ∣ − m − μ ∣ ≤ 1 / 2 , 0 ≤ u ≤ 1 / 10000 , 0 ≤ v , w ≤ 1 } , \mathcal C_\mu=\{(m,u,v,w):|-m-\mu|\leq1/2,
\ 0\leq u\leq1/10000,\ 0\leq v,w\leq1\}, C μ = {( m , u , v , w ) : ∣ − m − μ ∣ ≤ 1/2 , 0 ≤ u ≤ 1/10000 , 0 ≤ v , w ≤ 1 } ,
ω − ( y ) = s ( − y m , y u , y v , y w ) , H ( y ) = F ( y ) / ω − ( y ) . \omega_-(y)=s(-y_m,y_u,y_v,y_w),\qquad H(y)=F(y)/\omega_-(y). ω − ( y ) = s ( − y m , y u , y v , y w ) , H ( y ) = F ( y ) / ω − ( y ) .
For a normalized trajectory write
β ( t ) = Π ( α x , t 0 ( t ) ) , A ( t ) = 1 + ( α x , t 0 ( t ) ) 0 , I = I max ( x , t 0 ) . \beta(t)=\Pi(\alpha_{x,t_0}(t)),\quad A(t)=1+(\alpha_{x,t_0}(t))_0,
\quad I=I_{\max}(x,t_0). β ( t ) = Π ( α x , t 0 ( t )) , A ( t ) = 1 + ( α x , t 0 ( t ) ) 0 , I = I m a x ( x , t 0 ) .
For p = ( μ , u , w ) ∈ R 3 p=(\mu,u,w)\in\mathbb R^3 p = ( μ , u , w ) ∈ R 3 , set e ( p ) = ( − μ , u , 1 , w ) e(p)=(-\mu,u,1,w) e ( p ) = ( − μ , u , 1 , w ) ,
x p = Ξ ( e ( p ) ) x_p=\Xi(e(p)) x p = Ξ ( e ( p )) , and
T − ( p ) = inf { t > 0 : t ∈ I max ( x p , 0 ) , ( Ψ 0 ( e ( p ) , t ) ) w = 1 } , P − ( p ) = Ψ 0 ( e ( p ) , T − ( p ) ) . T_-(p)=\inf\{t>0:t\in I_{\max}(x_p,0),\ (\Psi_0(e(p),t))_w=1\},
\qquad P_-(p)=\Psi_0(e(p),T_-(p)). T − ( p ) = inf { t > 0 : t ∈ I m a x ( x p , 0 ) , ( Ψ 0 ( e ( p ) , t ) ) w = 1 } , P − ( p ) = Ψ 0 ( e ( p ) , T − ( p )) .
Let V − ( p ) V_-(p) V − ( p ) mean that this infimum is a least element, the full interval
[ 0 , T − ( p ) ] [0,T_-(p)] [ 0 , T − ( p )] lies in the maximal domain with positive A A A , the growing wall
is below one before the endpoint, and its normalized-time derivative is
strictly positive at the endpoint. The infimum has its total real-order meaning.
Write e + ( R , u , w ) = ( 1 + R 2 − 1 , u , 1 , w ) e_+(R,u,w)=(1+\sqrt{R^2-1},u,1,w) e + ( R , u , w ) = ( 1 + R 2 − 1 , u , 1 , w ) ,
e − ( R , u , w ) = ( 1 − R 2 − 1 , u , 1 , w ) e_-(R,u,w)=(1-\sqrt{R^2-1},u,1,w) e − ( R , u , w ) = ( 1 − R 2 − 1 , u , 1 , w ) ,
p − ( R , u , w ) = ( R 2 − 1 − 1 , u , w ) p_-(R,u,w)=(\sqrt{R^2-1}-1,u,w) p − ( R , u , w ) = ( R 2 − 1 − 1 , u , w ) , and
R ( m , u , v , w ) = ( − m , u , w , v ) \mathcal R(m,u,v,w)=(-m,u,w,v) R ( m , u , v , w ) = ( − m , u , w , v ) .
The physical connection coordinates are
C ( p ) = ( ( − P − ( p ) 0 − 1 ) 2 + 1 , P − ( p ) 1 , P − ( p ) 2 ) . \mathscr C(p)=\left(\sqrt{(-P_-(p)_0-1)^2+1},P_-(p)_1,P_-(p)_2\right). C ( p ) = ( ( − P − ( p ) 0 − 1 ) 2 + 1 , P − ( p ) 1 , P − ( p ) 2 ) .
Below T T T denotes the canonical core return time from e + e_+ e + and
F ( Y ) = η ( Ψ 0 ( e + ( Y ) , T ( Y ) ) ) F(Y)=\eta(\Psi_0(e_+(Y),T(Y))) F ( Y ) = η ( Ψ 0 ( e + ( Y ) , T ( Y ))) its radial and wall coordinates.
Let R ( Y ) = C ( p − ( Y ) ) \mathscr R(Y)=\mathscr C(p_-(Y)) R ( Y ) = C ( p − ( Y )) , t r ( Y ) = T − ( p − ( Y ) ) t_r(Y)=T_-(p_-(Y)) t r ( Y ) = T − ( p − ( Y )) ,
G = R ∘ F G=\mathscr R\circ F G = R ∘ F , and t G ( Y ) = T ( Y ) + t r ( F ( Y ) ) t_G(Y)=T(Y)+t_r(F(Y)) t G ( Y ) = T ( Y ) + t r ( F ( Y )) .
A cone direction at Y Y Y has d 0 = 1 d_0=1 d 0 = 1 ,
∣ d 1 ∣ ≤ Y 1 |d_1|\leq\sqrt{Y_1} ∣ d 1 ∣ ≤ Y 1 , ∣ d 2 ∣ ≤ Y 2 |d_2|\leq\sqrt{Y_2} ∣ d 2 ∣ ≤ Y 2 .
For a map H H H with positive output walls, its positive cone property means
d H ( Y ) d dH(Y)d d H ( Y ) d has positive radial component and
∣ ( d H ( Y ) d ) i ∣ ≤ H ( Y ) i ( d H ( Y ) d ) 0 |(dH(Y)d)_i|\leq\sqrt{H(Y)_i}(dH(Y)d)_0 ∣ ( d H ( Y ) d ) i ∣ ≤ H ( Y ) i ( d H ( Y ) d ) 0 for i = 1 , 2 i=1,2 i = 1 , 2 .
For real variables p , s , a , b , c p,s,a,b,c p , s , a , b , c , set
K = a 2 + b 2 + c 2 − 2 ( a b + b c + c a ) , S = p 2 + s 2 , C = S + K . K=a^2+b^2+c^2-2(ab+bc+ca),\qquad S=p^2+s^2,\qquad C=S+K. K = a 2 + b 2 + c 2 − 2 ( ab + b c + c a ) , S = p 2 + s 2 , C = S + K .
The shear components and wall rates are
P = K p − 2 a 2 + b 2 + c 2 + a b − 2 b c + a c , P=Kp-2a^2+b^2+c^2+ab-2bc+ac, P = K p − 2 a 2 + b 2 + c 2 + ab − 2 b c + a c ,
Q = K s + 3 ( − b 2 + c 2 + a b − a c ) , Q=Ks+\sqrt{3}(-b^2+c^2+ab-ac), Q = K s + 3 ( − b 2 + c 2 + ab − a c ) ,
r 1 = − S + 2 p , r 2 = − S − p + 3 s , r 3 = − S − p − 3 s . r_1=-S+2p,\qquad r_2=-S-p+\sqrt{3}s,\qquad r_3=-S-p-\sqrt{3}s. r 1 = − S + 2 p , r 2 = − S − p + 3 s , r 3 = − S − p − 3 s .
These functions define the normalized vacuum Bianchi IX vector field
( P , Q , r 1 a , r 2 b , r 3 c ) (P,Q,r_1a,r_2b,r_3c) ( P , Q , r 1 a , r 2 b , r 3 c ) .
For y = ( m , u , v , w ) ∈ R 4 y=(m,u,v,w)\in\mathbb R^4 y = ( m , u , v , w ) ∈ R 4 , define
K ( u , v , w ) = u 2 + v 2 + w 2 − 2 ( u v + v w + w u ) , κ = u ( v + w − u ) , K(u,v,w)=u^2+v^2+w^2-2(uv+vw+wu),\qquad \kappa=u(v+w-u), K ( u , v , w ) = u 2 + v 2 + w 2 − 2 ( uv + v w + w u ) , κ = u ( v + w − u ) ,
F m = − v 2 + w 2 + u ( v − w ) − m κ , F u = 1 2 ( 1 − m 2 − ( v − w ) 2 + u 2 ) u , F_m=-v^2+w^2+u(v-w)-m\kappa,\qquad
F_u=\tfrac12(1-m^2-(v-w)^2+u^2)u, F m = − v 2 + w 2 + u ( v − w ) − mκ , F u = 2 1 ( 1 − m 2 − ( v − w ) 2 + u 2 ) u ,
F v = ( m − 1 − κ ) v , F w = ( − m − 1 − κ ) w , F = ( F m , F u , F v , F w ) , F_v=(m-1-\kappa)v,\qquad F_w=(-m-1-\kappa)w,\qquad
F=(F_m,F_u,F_v,F_w), F v = ( m − 1 − κ ) v , F w = ( − m − 1 − κ ) w , F = ( F m , F u , F v , F w ) ,
and E ( m , v ) = ( m − 1 ) 2 + v 2 E(m,v)=(m-1)^2+v^2 E ( m , v ) = ( m − 1 ) 2 + v 2 .
For x = ( p , s , a , b , c ) x=(p,s,a,b,c) x = ( p , s , a , b , c ) , put
ψ ( p , z ) = 3 z 1 + p , Π ( x ) = ( ψ ( p , s ) , ψ ( p , a ) , ψ ( p , b ) , ψ ( p , c ) ) . \psi(p,z)=\frac{\sqrt3\,z}{1+p},\qquad
\Pi(x)=(\psi(p,s),\psi(p,a),\psi(p,b),\psi(p,c)). ψ ( p , z ) = 1 + p 3 z , Π ( x ) = ( ψ ( p , s ) , ψ ( p , a ) , ψ ( p , b ) , ψ ( p , c )) .
For y = ( m , u , v , w ) y=(m,u,v,w) y = ( m , u , v , w ) , set D ( y ) = 3 + m 2 + K ( u , v , w ) D(y)=3+m^2+K(u,v,w) D ( y ) = 3 + m 2 + K ( u , v , w ) and
Ξ A ( y ) = ( A − 1 , A m 3 , A u 3 , A v 3 , A w 3 ) , Ξ ( y ) = Ξ 6 / D ( y ) ( y ) . \Xi_A(y)=\left(A-1,\frac{Am}{\sqrt3},\frac{Au}{\sqrt3},
\frac{Av}{\sqrt3},\frac{Aw}{\sqrt3}\right),\qquad
\Xi(y)=\Xi_{6/D(y)}(y). Ξ A ( y ) = ( A − 1 , 3 A m , 3 A u , 3 A v , 3 A w ) , Ξ ( y ) = Ξ 6/ D ( y ) ( y ) .
Write N ( x ) = ( P , Q , r 1 a , r 2 b , r 3 c ) N(x)=(P,Q,r_1a,r_2b,r_3c) N ( x ) = ( P , Q , r 1 a , r 2 b , r 3 c ) for the normalized vector field
and C ( x ) = C ( p , s , a , b , c ) \mathcal C(x)=C(p,s,a,b,c) C ( x ) = C ( p , s , a , b , c ) for its constraint.
The normalized and projective state spaces are R 5 \mathbb R^5 R 5 and R 4 \mathbb R^4 R 4
with their finite-product norms. The maps Π , Ξ , D , F \Pi,\Xi,D,F Π , Ξ , D , F act on these state spaces.
The projective vector field in normalized time is
G ( y ) = 6 D ( y ) F ( y ) . G(y)=\frac6{D(y)}F(y). G ( y ) = D ( y ) 6 F ( y ) .
Write X = R 5 X=\mathbb R^5 X = R 5 , Y = R 4 Y=\mathbb R^4 Y = R 4 , and let α x , t 0 \alpha_{x,t_0} α x , t 0 be the
maximal solution of α ′ = N ( α ) \alpha'=N(\alpha) α ′ = N ( α ) with initial value x x x at t 0 t_0 t 0
and domain I max ( x , t 0 ) I_{\max}(x,t_0) I m a x ( x , t 0 ) . Put
J x , t 0 ( t ) = d x α x , t 0 ( t ) , Ψ t 0 ( y , t ) = Π ( α Ξ ( y ) , t 0 ( t ) ) , J_{x,t_0}(t)=d_x\alpha_{x,t_0}(t),\qquad
\Psi_{t_0}(y,t)=\Pi(\alpha_{\Xi(y),t_0}(t)), J x , t 0 ( t ) = d x α x , t 0 ( t ) , Ψ t 0 ( y , t ) = Π ( α Ξ ( y ) , t 0 ( t )) ,
J y , t 0 ( t ) = d Π α Ξ ( y ) , t 0 ( t ) ∘ J Ξ ( y ) , t 0 ( t ) ∘ d Ξ y . \mathcal J_{y,t_0}(t)=d\Pi_{\alpha_{\Xi(y),t_0}(t)}
\circ J_{\Xi(y),t_0}(t)\circ d\Xi_y. J y , t 0 ( t ) = d Π α Ξ ( y ) , t 0 ( t ) ∘ J Ξ ( y ) , t 0 ( t ) ∘ d Ξ y .
For Y = ( k , u , w ) ∈ R 3 Y=(k,u,w)\in\mathbb R^3 Y = ( k , u , w ) ∈ R 3 , define
e − ( Y ) = ( 1 − k 2 − 1 , u , 1 , w ) , x Y = Ξ ( e − ( Y ) ) , β Y ( t ) = Ψ 0 ( e − ( Y ) , t ) , g ( x ) = ( Π ( x ) ) v . e_-(Y)=(1-\sqrt{k^2-1},u,1,w),\quad x_Y=\Xi(e_-(Y)),\quad
\beta_Y(t)=\Psi_0(e_-(Y),t),\quad g(x)=(\Pi(x))_v. e − ( Y ) = ( 1 − k 2 − 1 , u , 1 , w ) , x Y = Ξ ( e − ( Y )) , β Y ( t ) = Ψ 0 ( e − ( Y ) , t ) , g ( x ) = ( Π ( x ) ) v .
For any real height η \eta η , put
H η , Y = { t > 0 : t ∈ I max ( x Y , 0 ) , g ( α x Y , 0 ( t ) ) = η } , H_{\eta,Y}=\{t>0:t\in I_{\max}(x_Y,0),\ g(\alpha_{x_Y,0}(t))=\eta\}, H η , Y = { t > 0 : t ∈ I m a x ( x Y , 0 ) , g ( α x Y , 0 ( t )) = η } ,
T η ( Y ) = inf H η , Y , P η ( Y ) = β Y ( T η ( Y ) ) . T_\eta(Y)=\inf H_{\eta,Y},\qquad P_\eta(Y)=\beta_Y(T_\eta(Y)). T η ( Y ) = inf H η , Y , P η ( Y ) = β Y ( T η ( Y )) .
The infimum uses the total real-order convention. Let
TailValid η ( Y ) \operatorname{TailValid}_\eta(Y) TailValid η ( Y ) mean that T η ( Y ) T_\eta(Y) T η ( Y ) is the least
element of H η , Y H_{\eta,Y} H η , Y , and, writing T = T η ( Y ) T=T_\eta(Y) T = T η ( Y ) , that
t ∈ I max ( x Y , 0 ) , 1 + ( α x Y , 0 ( t ) ) 0 > 0 ( 0 ≤ t ≤ T ) , t\in I_{\max}(x_Y,0),\quad 1+(\alpha_{x_Y,0}(t))_0>0
\quad(0\leq t\leq T), t ∈ I m a x ( x Y , 0 ) , 1 + ( α x Y , 0 ( t ) ) 0 > 0 ( 0 ≤ t ≤ T ) ,
g ( α x Y , 0 ( t ) ) > η ( 0 ≤ t < T ) , g(\alpha_{x_Y,0}(t))>\eta\quad(0\leq t<T), g ( α x Y , 0 ( t )) > η ( 0 ≤ t < T ) ,
d g α x Y , 0 ( t ) N ( α x Y , 0 ( t ) ) < 0 , ∣ ( Π ( α x Y , 0 ( t ) ) ) w ∣ < 1 / 2 ( 0 ≤ t ≤ T ) . dg_{\alpha_{x_Y,0}(t)}N(\alpha_{x_Y,0}(t))<0,\quad
|(\Pi(\alpha_{x_Y,0}(t)))_w|<1/2\quad(0\leq t\leq T). d g α x Y , 0 ( t ) N ( α x Y , 0 ( t )) < 0 , ∣ ( Π ( α x Y , 0 ( t )) ) w ∣ < 1/2 ( 0 ≤ t ≤ T ) .
All vector and operator norms use the finite-product supremum norms.
For y ∈ R 4 y\in\mathbb R^4 y ∈ R 4 , put x y = Ξ ( y ) x_y=\Xi(y) x y = Ξ ( y ) ,
T + ( y ) = inf { t > 0 : t ∈ I max ( x y , 0 ) , ( Ψ 0 ( y , t ) ) v = 1 } , P + ( y ) = Ψ 0 ( y , T + ( y ) ) . T_+(y)=\inf\{t>0:t\in I_{\max}(x_y,0),\ (\Psi_0(y,t))_v=1\},
\qquad P_+(y)=\Psi_0(y,T_+(y)). T + ( y ) = inf { t > 0 : t ∈ I m a x ( x y , 0 ) , ( Ψ 0 ( y , t ) ) v = 1 } , P + ( y ) = Ψ 0 ( y , T + ( y )) .
Let V + ( y ) V_+(y) V + ( y ) mean that this infimum is a least element, the full interval
[ 0 , T + ( y ) ] [0,T_+(y)] [ 0 , T + ( y )] lies in the maximal domain with
1 + ( α x y , 0 ( t ) ) 0 > 0 1+(\alpha_{x_y,0}(t))_0>0 1 + ( α x y , 0 ( t ) ) 0 > 0 , the active wall
is below one before the endpoint, and its normalized-time derivative is
strictly positive throughout the interval. The infimum has its total
real-order meaning.
For y = ( m , u , v , w ) y=(m,u,v,w) y = ( m , u , v , w ) define the cyclic chart by
H ( y ) = ( m + 1 ) 2 + K ( u , v , w ) , A ( y ) = ( 1 − 4 ( m + 1 ) / H , 4 v / H , 4 w / H , 4 u / H ) . H(y)=(m+1)^2+K(u,v,w),\qquad
\mathcal A(y)=(1-4(m+1)/H,4v/H,4w/H,4u/H). H ( y ) = ( m + 1 ) 2 + K ( u , v , w ) , A ( y ) = ( 1 − 4 ( m + 1 ) / H , 4 v / H , 4 w / H , 4 u / H ) .
Its normalized symmetry is
A ( p , s , a , b , c ) = ( ( − p + 3 s ) / 2 , ( − 3 p − s ) / 2 , b , c , a ) . A(p,s,a,b,c)=((-p+\sqrt3s)/2,(-\sqrt3p-s)/2,b,c,a). A ( p , s , a , b , c ) = (( − p + 3 s ) /2 , ( − 3 p − s ) /2 , b , c , a ) .
Put z h ( Y ) = A ( P h ( Y ) ) z_h(Y)=\mathcal A(P_h(Y)) z h ( Y ) = A ( P h ( Y )) and
T ( h , Y ) = T h ( Y ) + T + ( z h ( Y ) ) , P ( h , Y ) = P + ( z h ( Y ) ) , x Y c = A Ξ ( e − ( Y ) ) . \mathcal T(h,Y)=T_h(Y)+T_+(z_h(Y)),\qquad
\mathcal P(h,Y)=P_+(z_h(Y)),\qquad x_Y^c=A\Xi(e_-(Y)). T ( h , Y ) = T h ( Y ) + T + ( z h ( Y )) , P ( h , Y ) = P + ( z h ( Y )) , x Y c = A Ξ ( e − ( Y )) .
Write r ( m , v ) = ( m − 1 ) 2 + v 2 r(m,v)=\sqrt{(m-1)^2+v^2} r ( m , v ) = ( m − 1 ) 2 + v 2 and g ∗ ( x ) = ( Π ( x ) ) v g_*(x)=(\Pi(x))_v g ∗ ( x ) = ( Π ( x ) ) v .
In the era formulas below, F F F denotes the core return map and
G = R ∘ F G=\mathscr R\circ F G = R ∘ F its composition with reflection.
For Z = ( R , u , w ) Z=(R,u,w) Z = ( R , u , w ) use the natural height h ∗ ( Z ) = η ( ( R − 2 ) / 2 ) J h_*(Z)=\eta((R-2)/2)^J h ∗ ( Z ) = η (( R − 2 ) /2 ) J and define
S ∗ ( Z ) = P ( h ∗ ( Z ) , Z ) S_*(Z)=\mathcal P(h_*(Z),Z) S ∗ ( Z ) = P ( h ∗ ( Z ) , Z ) ,
R ∗ ( Z ) = r ( S ∗ ( Z ) 0 , S ∗ ( Z ) 2 ) R_*(Z)=r(S_*(Z)_0,S_*(Z)_2) R ∗ ( Z ) = r ( S ∗ ( Z ) 0 , S ∗ ( Z ) 2 ) ,
Q ∗ ( Z ) = 2 / R ∗ ( Z ) Q_*(Z)=2/R_*(Z) Q ∗ ( Z ) = 2/ R ∗ ( Z ) and t ∗ ( Z ) = T ( h ∗ ( Z ) , Z ) t_*(Z)=\mathcal T(h_*(Z),Z) t ∗ ( Z ) = T ( h ∗ ( Z ) , Z ) .
The complete era maps are
Z m = F ∘ G m , S m = S ∗ ∘ Z m , R m = R ∗ ∘ Z m , P m = 2 / R m . Z_m=F\circ G^m,\qquad S_m=S_*\circ Z_m,\qquad
R_m=R_*\circ Z_m,\qquad P_m=2/R_m. Z m = F ∘ G m , S m = S ∗ ∘ Z m , R m = R ∗ ∘ Z m , P m = 2/ R m .
For a graph Γ = ( U , W ) \Gamma=(U,W) Γ = ( U , W ) write Γ [ r ] = ( r , U ( r ) , W ( r ) ) \Gamma[r]=(r,U(r),W(r)) Γ [ r ] = ( r , U ( r ) , W ( r )) ,
ϕ m ( r ) = P m ( Γ [ r ] ) \phi_m(r)=P_m(\Gamma[r]) ϕ m ( r ) = P m ( Γ [ r ]) , k m ( r ) = R m ( Γ [ r ] ) k_m(r)=R_m(\Gamma[r]) k m ( r ) = R m ( Γ [ r ]) ,
u m ( r ) = S m ( Γ [ r ] ) 1 u_m(r)=S_m(\Gamma[r])_1 u m ( r ) = S m ( Γ [ r ] ) 1 , w m ( r ) = S m ( Γ [ r ] ) 3 w_m(r)=S_m(\Gamma[r])_3 w m ( r ) = S m ( Γ [ r ] ) 3 .
Let Inv a , b ( f ) \operatorname{Inv}_{a,b}(f) Inv a , b ( f ) denote Lean's total choice inverse
invFunOn f [ a , b ] \operatorname{invFunOn}f\,[a,b] invFunOn f [ a , b ] . For
a = 2 ( m + 1 + β ) a=2(m+1+\beta) a = 2 ( m + 1 + β ) , b = 2 ( m + 2 − β ) b=2(m+2-\beta) b = 2 ( m + 2 − β ) , define
g m = Inv a , b ( ϕ m ) , h m ( y ) = 2 / g m ( y ) . g_m=\operatorname{Inv}_{a,b}(\phi_m),\qquad h_m(y)=2/g_m(y). g m = Inv a , b ( ϕ m ) , h m ( y ) = 2/ g m ( y ) .
Write γ n ( y ) = 1 / ( n + y ) \gamma_n(y)=1/(n+y) γ n ( y ) = 1/ ( n + y ) for the Gauss inverse branch.
The retained phase set is
H N = ⋃ m < N ( h m ( 1 − 2 β ) , h m ( 2 β ) ) \mathcal H_N=\bigcup_{m<N}(h_m(1-2\beta),h_m(2\beta)) H N = ⋃ m < N ( h m ( 1 − 2 β ) , h m ( 2 β )) .
Write x ( Y ) = Ξ ( e + ( Y ) ) x(Y)=\Xi(e_+(Y)) x ( Y ) = Ξ ( e + ( Y )) , Φ t s ( x ) = α x , s ( t ) \Phi^s_t(x)=\alpha_{x,s}(t) Φ t s ( x ) = α x , s ( t ) and I ( x , s ) I(x,s) I ( x , s )
for its maximal domain. Set Y j = G j X Y_j=G^jX Y j = G j X , Z = F ( Y m ) Z=F(Y_m) Z = F ( Y m ) ,
N m ( X ) = ( R m ( X ) , S m ( X ) 1 , S m ( X ) 3 ) N_m(X)=(R_m(X),S_m(X)_1,S_m(X)_3) N m ( X ) = ( R m ( X ) , S m ( X ) 1 , S m ( X ) 3 ) , and
d m ( X ) = ∑ j < m t G ( Y j ) + T ( Y m ) + t ∗ ( Z ) . d_m(X)=\sum_{j<m}t_G(Y_j)+T(Y_m)+t_*(Z). d m ( X ) = j < m ∑ t G ( Y j ) + T ( Y m ) + t ∗ ( Z ) .
The six axis frames realize all permutations of the normalized walls
and diagonal shears. Write L m L_m L m for the frame obtained by m m m swaps
followed by the cyclic permutation.
The event itinerary I m ( X ) \mathcal I_m(X) I m ( X ) has the following meaning.
For j ≤ m j\le m j ≤ m , the radius of Y j Y_j Y j exceeds two, the entry is an upward
unit-wall crossing, its core first return is valid, and its endpoint
is e − ( F ( Y j ) ) e_-(F(Y_j)) e − ( F ( Y j )) . For j < m j<m j < m the exit radius exceeds four, and the
first positive unit-wall hit in the swapped chart reaches e + ( Y j + 1 ) e_+(Y_{j+1}) e + ( Y j + 1 ) ,
the reflection of the endpoint at time t G ( Y j ) t_G(Y_j) t G ( Y j ) . The final exit has
radius strictly between two and four. In the cycled exit chart its
first positive unit-wall hit occurs at t ∗ ( Z ) t_*(Z) t ∗ ( Z ) , has state S ∗ ( Z ) S_*(Z) S ∗ ( Z )
and positive event rate. Finally ⌊ X 0 / 2 ⌋ = m + 1 \lfloor X_0/2\rfloor=m+1 ⌊ X 0 /2 ⌋ = m + 1 .
For a budget cap b b b define A m ( b ) A_m(b) A m ( b ) by the conditions on ( B , X ) (B,X) ( B , X )
0 < B ≤ b , m < ⌊ B − σ ⌋ , X 1 , X 2 > 0 , X 1 + X 2 ≤ B , m + 1 + B σ ≤ X 0 / 2 ≤ m + 2 − B σ . 0<B\le b,\quad m<\lfloor B^{-\sigma}\rfloor,\quad X_1,X_2>0,\quad
X_1+X_2\le B,\quad m+1+B^\sigma\le X_0/2\le m+2-B^\sigma. 0 < B ≤ b , m < ⌊ B − σ ⌋ , X 1 , X 2 > 0 , X 1 + X 2 ≤ B , m + 1 + B σ ≤ X 0 /2 ≤ m + 2 − B σ .
The selected domain D m ( b ) D_m(b) D m ( b ) additionally requires
2 B σ < P m ( X ) < 1 − 2 B σ 2B^\sigma<P_m(X)<1-2B^\sigma 2 B σ < P m ( X ) < 1 − 2 B σ ; the budget return is
F m ( B , X ) = ( B 4 / 3 , N m ( X ) ) \mathcal F_m(B,X)=(B^{4/3},N_m(X)) F m ( B , X ) = ( B 4/3 , N m ( X )) .
In a small-budget assertion there exists 0 < δ ≤ 1 / 40000 0<\delta\le1/40000 0 < δ ≤ 1/40000 such
that for every 0 < η ≤ δ 0<\eta\le\delta 0 < η ≤ δ , J ∈ N J\in\mathbb N J ∈ N with J ≥ 20 J\ge20 J ≥ 20 ,
0 < σ < 1 0<\sigma<1 0 < σ < 1 and 2 J σ < 1 2J\sigma<1 2 J σ < 1 , the stated constants can be chosen.
Let p p p be a budget and core state surviving all selected returns at
cap b b b . Its successive digits are a n a_n a n , its transported states are
X n X_n X n , its phases are y n = 2 / ( X n ) 0 y_n=2/(X_n)_0 y n = 2/ ( X n ) 0 , and m n = a n − 1 m_n=a_n-1 m n = a n − 1 . Put
d n = d m n ( X n ) , s n = ∑ j < n d j , A 0 = 1 , A n + 1 = L m n A n . d_n=d_{m_n}(X_n),\qquad s_n=\sum_{j<n}d_j,\qquad
A_0=1,\quad A_{n+1}=L_{m_n}A_n. d n = d m n ( X n ) , s n = j < n ∑ d j , A 0 = 1 , A n + 1 = L m n A n .
Frame indices use the chosen composition on the six labels. For restart
data w = ( ( i , s ) , ( B , X ) ) w=((i,s),(B,X)) w = (( i , s ) , ( B , X )) , let t n = s + s n t_n=s+s_n t n = s + s n and let P n P_n P n denote the
frame with index chosen for A n Q i A_n Q_i A n Q i , where Q i Q_i Q i is the initial
frame of label i i i . A restart witness for x x x requires
s > 0 s>0 s > 0 , s ∈ I ( x , 0 ) s\in I(x,0) s ∈ I ( x , 0 ) and a survivor with initial data ( B , X ) (B,X) ( B , X ) ,
full era statistics, and entry e + ( X ) = Π ( Q i Φ s 0 ( x ) ) e_+(X)=\Pi(Q_i\Phi^0_s(x)) e + ( X ) = Π ( Q i Φ s 0 ( x )) .
Assume for each m m m that D m ( b ) D_m(b) D m ( b ) is measurable and the restricted
map F m : D m ( b ) → R × R 3 \mathcal F_m:D_m(b)\to\mathbb R\times\mathbb R^3 F m : D m ( b ) → R × R 3 is measurable.
On the product of restart data and the survivor subtype, the map
( w , p ) ⟼ ( index P n ( w , p ) ) n ≥ 0 (w,p)\longmapsto (\operatorname{index}P_n(w,p))_{n\ge0} ( w , p ) ⟼ ( index P n ( w , p ) ) n ≥ 0
is measurable into sequences of six-valued frame labels.