Topics (374k) Articles (387k) Users (410) Discussions (242) Comments (383) Files (13k) New article
A Slater determinant extends two-particle antisymmetrization to fermions. Here contains position and spin or other internal variables. Distinct orthonormal one-particle states give the normalized wavefunction displayed in the title. Repeating a one-particle state repeats a column of the determinant, so the wavefunction vanishes. Exchanging particle slots exchanges rows and reverses its sign. A general fermionic quantum state can be a quantum superposition of Slater determinants; it need not be one Slater determinant.
At the centre of geodesic normal coordinates, expand the square of the Twisted Dirac operator. The diagonal terms give the rough Laplacian; the off-diagonal terms are . The tensor-product vector-bundle curvature is the sum of spin curvature and . Substituting spin curvature and using the Clifford algebra relations yields the scalar term : the four-generator contribution vanishes by the algebraic Bianchi identity and the contracted terms are the scalar curvature. This proves the displayed identity at every point.
For the defining representation of the special linear Lie algebra , the crystal basis is , with weights restricted to trace-zero diagonal matrices. Its dual is , with weights . Using the crystal tensor-product rule with lowering on the first factor when , the tensor square has highest vertices and , of highest weights , generating components of six and three vertices. The defining tensor dual has highest vertices and , generating components of eight and one vertices and weights . These encode the symmetric square plus exterior square, and the trace-free endomorphisms plus scalar identity, respectively. A crystal vertex labelled by a tensor pair need not represent that same undeformed ordinary simple tensor; the actual invariant vector is .
For a compact string embedding map coordinate, T-duality preserves its left-moving part and reverses its right-moving part. Consequently and . A Neumann boundary condition becomes a Dirichlet boundary condition and conversely. A D-brane wrapping the circle loses one spatial worldvolume dimension; a D-brane transverse to it gains one in the dual description.
For , the exact largest constituent dimension of a mixed SU(3) tensor representation isEvery constituent highest weight lies below , so its labels have the form for nonnegative integers . If both are positive, reducing each by their minimum increases both and strictly increases the dimension. The resulting boundary labels occur: antisymmetrize disjoint upper pairs into lower indices, or lower pairs into upper indices, then take the symmetric traceless component. This proves the maximum formula. For , the fully symmetric dimension is 21 but has dimension 24. For , the fully symmetric traceless dimension is the maximum.
The degree-three monomials , with , form a basis of this ten-dimensional highest-weight representation. Its highest monomial is , and and generate every basis monomial. Its Dynkin labels are , and the weight of a monomial is . In coordinates , the ten weights form four horizontal rows of lengths , all with weight multiplicity one. The baryon decuplet realizes this representation of approximate flavor symmetry.
// Target: special-relativity.bigb
For , contraction with the invariant symmetric bilinear form splits off the trivial line in the symmetric square of the defining special orthogonal group representation. Its null space is the traceless symmetric square. It contains a highest-weight vector of weight , and the Weyl dimension formula gives , exactly its dimension. Complete reducibility of compact-group representations therefore makes that null space irreducible. The entire symmetric square is reducible because of the invariant line.
For the defining -dimensional special linear Lie algebra module, with , write . The equivariant contraction is . The map is also equivariant, since is an invariant identity tensor. Direct differentiation gives , so the displayed direct sum follows. Its trace-free part is an irreducible representation of highest weight . Its highest-weight vector is ; the Weyl dimension formula gives dimension , exactly .
// Target: semisimple-lie-algebra.bigb
In a nontrivial symmetric balanced incomplete block design, . If is even, is odd. For every prime, the exponent in the left side is even and that in is even, so its exponent in must be even. Thus is a perfect square. This supplies an elementary necessary existence condition without claiming it is sufficient.
For an axisymmetric random velocity dispersion tensor with and , contracting with the line-of-sight unit vector gives the displayed mass-weighted velocity dispersion. A major-axis rotation amplitude projects as . By contrast, an azimuthally averaged line-of-sight streaming root-mean-square is when is the full in-plane streaming mean square. Aperture weights and the definition of the measured rotation statistic must match the intrinsic statistic.
In normalization , one Standard Model generation has left quark and lepton doublet hypercharges and , and right singlet hypercharges . Including colour multiplicity, . On every left doublet , and all right fields have , so the mixed weak-hypercharge gauge anomaly vanishes. The cubic left trace is , and the right trace is . Their difference is zero, proving generation-by-generation cancellation of these two anomalies.
Start the symmetric stochastic attrition process at , with , and let be the final first-population size divided by . The bound holds for all sufficiently large , depending on . At absorption, one coordinate is zero. If the first survives, the terminal squared difference is ; if it is extinguished, that difference is nonpositive. In either case the indicated deviation forces an error of at least from the limiting squared invariant. The initial rounding error and total conditional drift are only . Apply Azuma-Hoeffding inequality to the centered squared-population near-invariant for stochastic attrition, using its increments bounded by , to obtain the displayed exponent.
A spinor representation is a representation of a Spin group, or infinitesimally of a Special orthogonal Lie algebra, constructed from a Clifford algebra. In even dimensions it can split into two chiral spinor representations.
A fixed volume form makes wedge pairing on a symmetric form of signature . The exterior-square action of special linear group matrices preserves it. Its kernel is : a transformation acting trivially on every bivector preserves every two-plane and hence every line, so is scalar, with scalar square one. The derivative is injective and both groups have dimension fifteen, so the connected image is the full identity component. This is a concrete real spin-group cover.
Congruence on real symmetric two-by-two matrices preserves the quadratic form of signature when . Its kernel is and its derivative is injective: for every symmetric implies . Both Lie groups have dimension three, so the connected image is the full identity component. Also identifies with .
On two-by-two Hermitian matrices, the determinant of is . The action preserves it for . A kernel element is unitary and commutes with every Hermitian matrix, hence is . The derivative is injective and both real dimensions are six, giving the full proper orthochronous Lorentz group as the connected image.
Fix a volume form on a four-dimensional real symplectic vector space. Wedge pairing on its exterior square has signature . The symplectic group fixes the bivector inverse to the symplectic form. Its orthogonal complement is five-dimensional with signature after choosing the appropriate overall sign. The induced representation has kernel : identity action on the entire exterior square preserves every two-plane and thus every line, forcing a scalar transformation with square one. Its derivative is injective and both group dimensions are ten, so its image is the identity component of .
At fixed angular coordinates, differentiating the Cartesian coordinates with respect to radial distance gives this unit vector. It is the local direction of increasing radius in the spherical coordinate system.
A finite family of pairwise commuting normal operators on a finite-dimensional complex inner product space, commuting also with each other's adjoints, generates a commutative unital C-star algebra. Its finite maximal ideal space identifies the algebra with functions on finitely many points. The characteristic functions of those points pull back under the Gelfand transform to mutually orthogonal self-adjoint linear projections summing to the identity. Their ranges are the simultaneous eigenspaces, giving simultaneous diagonalization without choosing separate incompatible eigenbases.
A Specht filtration is a finite chain of submodules whose successive quotients are Specht modules. In positive characteristic it need not split and is not a composition series, because its Specht factors may themselves be reducible. Dimensions and ordinary lifted characters can still be added along the filtration.
Pinned article: Introduction to the OurBigBook Project
Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
Intro to OurBigBook
. Source. We have two killer features:
- topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculusArticles of different users are sorted by upvote within each article page. This feature is a bit like:
- a Wikipedia where each user can have their own version of each article
- a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.Figure 1. Screenshot of the "Derivative" topic page. View it live at: ourbigbook.com/go/topic/derivativeVideo 2. OurBigBook Web topics demo. Source. - local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
- to OurBigBook.com to get awesome multi-user features like topics and likes
- as HTML files to a static website, which you can host yourself for free on many external providers like GitHub Pages, and remain in full control
Figure 2. You can publish local OurBigBook lightweight markup files to either OurBigBook.com or as a static website.Figure 3. Visual Studio Code extension installation.Figure 5. . You can also edit articles on the Web editor without installing anything locally. Video 3. Edit locally and publish demo. Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension. - Infinitely deep tables of contents:
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact





