Under $g\mapsto {\Omega }^{2}g$ in dimension $d$, the Hodge star on $p$-forms scales by ${\Omega }^{d-2p}$. For gauge curvature, $d=4,p=2$, so the star and the action $-g_{\mathrm{YM}}^{-2}\int \mathrm{tr}(F\wedge \ast F)$ are unchanged. Dilation therefore changes the instanton size modulus without changing the classical action. Quantum running of the coupling can break this classical scale invariance.

After quotienting infinitesimal worldsheet diffeomorphisms and Weyl transformations, choose a metric variation orthogonal to the gauge directions. Orthogonality to Weyl scaling makes its trace zero; the formal adjoint of the worldsheet conformal Killing operator makes its divergence zero. These are transverse-traceless variations of the two-dimensional metric. In a local conformal complex coordinate, their nonzero components satisfy ${\partial }_{\bar{z}}{t}_{zz}=0$ and its conjugate, linking them to holomorphic quadratic differentials.

The worldsheet conformal Killing group is the connected residual group of conformal automorphisms of the chosen compact Riemann surface. Its infinitesimal vectors satisfy the Conformal Killing equation, or $P_{1}v=0$ for the worldsheet diffeomorphism ghost operator. Its complex dimensions are three on a sphere, one on a torus, and zero for genus at least two. The sphere group consists of Möbius transformations, while the torus's connected group is translation. Additional discrete automorphisms are handled by the moduli quotient rather than counted as continuous zero modes.

In two dimensions the metric variation splits into a scalar trace and the trace-free diffeomorphism operator $(P_{1}v{)}_{ab}={\nabla }_a{v}_b+{\nabla }_b{v}_a-g_{ab}\nabla \cdot v$. Integrating the Weyl parameter in the inverse Faddeev-Popov determinant removes the trace delta function. The remaining determinant is exponentiated by an anticommuting vector ghost and symmetric trace-free antighost, yielding the two chiral $b\bar{\partial }c$ terms. Conformal Killing vectors and moduli are zero modes treated separately from this local determinant.

In conformal gauge, let the odd left-acting BRST differential act by $sX=c^{+}{\partial }_{+}X+c^{-}{\partial }_{-}X$ and $s{c}^{\pm }=c^{\pm }{\partial }_{\pm }{c}^{\pm }$. The graded Leibniz rule gives the displayed expression for $s^{2}X$. It vanishes using the ghost equations of motion ${\partial }_{-}{c}^{+}={\partial }_{+}{c}^{-}=0$, but it is not zero for arbitrary off-shell fields. For independent Grassmann variables $\xi ,\rho$, take $c^{+}=\xi$, $c^{-}=\rho {\sigma }^{+}$ and $X={\sigma }^{-}$; then $s^{2}X=-\xi \rho \ne 0$. Each ghost itself satisfies $s^2{c}^{\pm }=0$ algebraically. With the eliminated-antighost transformation $s{b}_{\pm \pm }=i{\theta }_{\pm \pm }/{\alpha }^{\prime }$ and $s{\theta }_{\pm \pm }=0$ on the solution space, the antighosts are nilpotent too. This on-shell closure is compatible with an off-shell total-derivative variation of the gauge-fixed action. A full off-shell BRST quantization uses the complete gauge transformation and, where required, auxiliary fields rather than silently dropping mixed ghost derivatives.

For the relativistic particle action $S=(m/2)\int [g_{\mu \nu }{\dot{x}}^{\mu }{\dot{x}}^{\nu }/e-e]d\lambda$, varying the worldline einbein gives $g_{\mu \nu }{\dot{x}}^{\mu }{\dot{x}}^{\nu }=-e^2$. On the positive-einbein branch the proper time satisfies $ds=ed\lambda$. A reparametrization with ${\lambda }^{\prime }=s$ sets the transformed einbein to one, making the geodesic equation affinely parametrized. This gauge choice is made after retaining the einbein mass shell constraint; fixing the action first would discard that equation. If the parameter interval is held fixed at both ends, its integrated proper length is a modulus and cannot be arbitrarily changed by endpoint-preserving transformations.

For arrivals added before the slot's offered service, $Z_k$ is the arriving work minus that service. With independent identically distributed increments of negative mean, the stationary queue workload has the law ${\sup }_{m\ge 0}{\sum }_{j=1}^m{Z}_j$. Iterating the recursion from the past gives this supremum; the strong law makes it finite. A different arrival/service ordering changes slot-boundary workload but requires its convention to be stated.

With lookback net input $z(s)=a(-s,0]-Cs$, the stable finite-buffer workload is ${\sup }_{t\ge 0}\min ({\sup }_{0\le s\le t}z(s),B+{\inf }_{0\le s\le t}z(s))$. Since $z(0)=0$, it lies between zero and B, and is at most the infinite-buffer supremum $q(a)={\sup }_{s\ge 0}z(s)$. For a constant-rate burst which builds exactly x work from an empty queue, no upper reflection occurs when $x\le B$ and both workloads equal x.

Use arrival rate v during the last t time units and the normal stable rate mu before that, where $\mu <C$. The lookback net input increases from zero to x over the burst, then decreases because the earlier net drift is negative. Its infinite-buffer workload is x, as is the finite-buffer workload map for capacity at least x. For a local convex path cost with density g and $g(\mu )=0$, its cost is $tg(v)=xg(v)/(v-C)$. These paths realize or approximate the optimal workload cost even if an optimizing duration is not attained.

For a stable input with path action $I(a)={\int }_{-\infty }^{0}g({\dot{a}}_s)ds$, a workload x requires some interval of length t with average input near $C+x/t$. Jensen inequality bounds its cost below by $tg(C+x/t)$; taking the supremum workload and then the infimum over t yields the displayed lower bound. Constant-rate burst paths give the matching upper bound. At zero the typical-rate path has zero cost; negative workloads have infinite rate. If no finite-cost rate exceeds C, every positive workload has infinite rate.

For independent and identically distributed arrivals with finite mean below service $c$, the strong law of large numbers makes the net cumulative input tend to minus infinity, so the supremum is finite almost surely. Applying the same formula to the past input gives a stationary solution of the Lindley recursion. This representation turns queue workload overflow into an event involving some lookback horizon.

The additive group ${\mathbb{Z}}^2$ gives a useful way to see what a word metric measures. Let $e_1=(1,0)$ and $e_2=(0,1)$, and choose the four-move generating set of a group $S=\{\pm e_1,\pm e_2\}$. Its Cayley graph is the square lattice. Each move changes exactly one coordinate by one, so the word length is the L1 norm, and the word metric is Manhattan distance:At least this many moves are necessary, and moving horizontally then vertically attains the bound. Bridson gives this square lattice as a basic Cayley graph example.^[ref]

Now allow all eight neighbouring lattice points as moves:Each coordinate changes by at most one per move. Use diagonal moves until the smaller displacement is exhausted, then use axis moves: the resulting word length is the maximum norm, and the word metric is Chebyshev distance. From $(0,0)$ to $(2,3)$, an $S$-route has five steps, while the $T$-route $(0,0),(1,1),(2,2),(2,3)$ has three.

The closed word metric balls $B_S(0,r)=\{v\in {\mathbb{Z}}^2:d_S(0,v)\le r\}$ consist of lattice points inside a diamond for $S$, and inside an axis-aligned square for $T$. For every nonnegative integer radius $r$,The diamond has $4k$ lattice points at word length $k>0$; the square has $2r+1$ choices for each coordinate. At radius three the counts are $25$ and $49$. These are discrete closed balls for Manhattan distance and Chebyshev distance; an Euclidean distance bound would instead select lattice points inside a Euclidean disk.

Restrict the spacetime spin connection to a spacelike hypersurface. With future unit normal $n$ and convention $k_{ij}=-g({\nabla }_{i}n,e_j)$, it differs from the intrinsic spin connection by the displayed extrinsic curvature term. Its spatial Dirac operator is the operator in the Witten spinor equation; replacing it by the intrinsic operator would omit the ADM momentum contribution.

On complete smooth asymptotically flat spin initial data without inner boundary, satisfying the Einstein constraints and the dominant energy condition, the Witten spinor equation admits a spinor approaching each prescribed asymptotic constant, under the standard weighted decay assumptions. The integrated Witten-Nester identity gives a coercive estimate and excludes a decaying homogeneous kernel. Weighted elliptic solvability then supplies the desired correction to a spinor extended from infinity. Positivity of the boundary integral is a conditional identity until this analytic existence step is supplied; see the rigorous analytic proof.

For zero viscosity, $S=f(r)\Sigma$ and constant $q>1$, set $\beta =2(q-1)$. On intervals where f>0, the wind-loaded Keplerian disk evolution equation becomes ${\Sigma }_t=\beta rf{\Sigma }_r+[\beta (2f+r{f}^{\prime })-f]\Sigma$. Multiplication by $f{r}^{2-1/\beta }$ and the displayed travel-time coordinate reduce it to constant-speed advection. Its profile is $g^{\prime }=F(x^{\prime }+t)$ and its characteristics move inward with $dr/dt=-\beta rf$. The weight accounts for mass loss as well as radial compression.

If the moment of inertia I changes slowly and wind-driven magnetic braking of a solar-type star has torque $-K{\Omega }^3$, then ${\Omega }^{-2}(t)={\Omega }^{-2}(t_0)+2K(t-t_0)/I$. At sufficiently late times within this unsaturated approximation, rotation scales as $t^{-1/2}$. This empirical main-sequence trend is not a universal law for saturated rapid rotators, changing stellar structure or every magnetic geometry.

There exists a probability measure on $C_0([0,\infty ),\mathbb{R})$ under which the coordinate process is standard Brownian motion, and its distribution there is unique. Construct consistent centered Gaussian finite-dimensional laws with covariance $\min (s,t)$ and use the Kolmogorov extension theorem. The fourth increment moment $3|t-s{|}^2$ supplies a continuous modification by the Kolmogorov continuity theorem. Its independent increments and normal increment distributions are unchanged. Uniqueness follows because coordinate evaluations at rational times generate the Borel sigma-algebra of continuous-path space.

For a scalar wave above a line with a Dirichlet half and a Neumann half, the boundary transform factors into ${\beta }_{+}(\alpha )=\sqrt{k+\alpha }$ and ${\beta }_{-}(\alpha )=\sqrt{k-\alpha }$. For $e^{-i\omega t}$, the limiting absorption principle puts $-k$ below and $k$ above the inversion contour. With Dirichlet conditions on the negative half-line and incident tangential wavenumber $a$, pole subtraction gives the diffracted trace $U_{+}=2i\sqrt{k-a}/[(\alpha +a)\sqrt{k+\alpha }]$. Its large-transform decay gives a bounded field with a square-root edge trace. The normal derivative has an inverse-square-root singularity on the Dirichlet half; it is identically zero on the Neumann half.

The Whitehead square of a class $\alpha \in {\pi }_{m}Y$ is $[\alpha ,\alpha ]\in {\pi }_{2m-1}Y$. For the identity class of an even-dimensional sphere, the Hopf invariant is two with the standard product-cell orientation: folding the two sphere summands makes the middle cohomology class of the mapping cone pull back to $a+b$ on $S^m\times S^m$, and $(a+b{)}^2=2ab$. For odd $m$, graded symmetry makes the square two-torsion, hence rationally zero.

Continuous-time Gaussian white noise is a random distribution rather than an ordinary finite-variance function at every time. Integrating it against deterministic kernels gives Gaussian random variables with covariance $q\int f(s)g(s)ds$. For independent isotropic components, a three-dimensional dot covariance has amplitude $3q$. An ordinary rapidly decaying force covariance approximates this model only above its correlation time.