Polymer adsorption

In differential geometry, a metaplectic structure is the symplectic analog of spin structure on orientable Riemannian manifolds. A metaplectic structure on a symplectic manifold allows one to define the symplectic spinor bundle, which is the Hilbert space bundle associated to the metaplectic structure via the metaplectic representation, giving rise to the notion of a symplectic spinor field in differential geometry.

Symplectic spin structures have wide applications to mathematical physics, in particular to quantum field theory where they are an essential ingredient in establishing the idea that symplectic spin geometry and symplectic Dirac operators may give valuable tools in symplectic geometry and symplectic topology. They are also of purely mathematical interest in differential geometry, algebraic topology, and K theory. They form the foundation for symplectic spin geometry.

Formal definition

A metaplectic structure on a symplectic manifold $(M,\omega )$ is an equivariant lift of the symplectic frame bundle $\pi _{\mathbf {R} }\colon {\mathbf {R} }\to M\,$ with respect to the double covering $\rho \colon {\mathrm {Mp} }(n,{\mathbb {R} })\to {\mathrm {Sp} }(n,{\mathbb {R} }).\,$ In other words, a pair $({\mathbf {P} },F_{\mathbf {P} })$ is a metaplectic structure on the principal bundle $\pi _{\mathbf {R} }\colon {\mathbf {R} }\to M\,$ when

a) $\pi _{\mathbf {P} }\colon {\mathbf {P} }\to M\,$ is a principal ${\mathrm {Mp} }(n,{\mathbb {R} })$-bundle over $M$,

b) $F_{\mathbf {P} }\colon {\mathbf {P} }\to {\mathbf {R} }\,$ is an equivariant $2$-fold covering map such that

$\pi _{\mathbf {R} }\circ F_{\mathbf {P} }=\pi _{\mathbf {P} }$ and $F_{\mathbf {P} }({\mathbf {p} }q)=F_{\mathbf {P} }({\mathbf {p} })\rho (q)$ for all ${\mathbf {p} }\in {\mathbf {P} }$ and $q\in {\mathrm {Mp} }(n,{\mathbb {R} }).$

The principal bundle $\pi _{\mathbf {P} }\colon {\mathbf {P} }\to M\,$ is also called the bundle of metaplectic frames over $M$.

Two metaplectic structures $({\mathbf {P} _{1}},F_{\mathbf {P} _{1}})$ and $({\mathbf {P} _{2}},F_{\mathbf {P} _{2}})$ on the same symplectic manifold $(M,\omega )$ are called equivalent if there exists a ${\mathrm {Mp} }(n,{\mathbb {R} })$-equivariant map $f\colon {\mathbf {P} _{1}}\to {\mathbf {P} _{2}}$ such that

$F_{\mathbf {P} _{2}}\circ f=F_{\mathbf {P} _{1}}$ and $f({\mathbf {p} }q)=f({\mathbf {p} })q$ for all ${\mathbf {p} }\in {\mathbf {P} _{1}}$ and $q\in {\mathrm {Mp} }(n,{\mathbb {R} }).$

Of course, in this case $F_{\mathbf {P} _{1}}$ and $F_{\mathbf {P} _{2}}$ are two equivalent double coverings of the symplectic frame ${\mathrm {Sp} }(n,{\mathbb {R} })$-bundle $\pi _{\mathbf {R} }\colon {\mathbf {R} }\to M\,$ of the given symplectic manifold $(M,\omega )$.

Obstruction

Since every symplectic manifold $M$ is necessarily of even dimension and orientable, one can prove that the topological obstruction to the existence of metaplectic structures is precisely the same as in Riemannian spin geometry. In other words, a symplectic manifold $(M,\omega )$ admits a metaplectic structures if and only if the second Stiefel-Whitney class $w_{2}(M)\in H^{2}(M,{\mathbb {Z} _{2}})$ of $M$ vanishes. In fact, the modulo $_{2}$ reduction of the first Chern class $c_{1}(M)\in H^{2}(M,{\mathbb {Z} })$ is the second Stiefel-Whitney class $w_{2}(M)$. Hence, $(M,\omega )$ admits metaplectic structures if and only if $c_{1}(M)$ is even, i.e., if and only if $w_{2}(M)$ is zero.

If this is the case, the isomorphy classes of metaplectic structures on $(M,\omega )$ are classified by the first cohomology group $H^{1}(M,{\mathbb {Z} _{2}})$ of $M$ with ${\mathbb {Z} _{2}}$-coefficients.

As the manifold $M$ is assumed to be oriented, the first Stiefel-Whitney class $w_{1}(M)\in H^{1}(M,{\mathbb {Z} _{2}})$ of $M$ vanishes too.

Examples

Manifolds admitting a metaplectic structure

• Phase spaces $(T^{\ast }N,\theta )\,,$ $N$ any orientable manifold.
• Complex projective spaces ${\mathbb {P} }^{2k+1}{\mathbb {C} }\,,$ $\,k\in {\mathbb {N} }_{0}\,.$ Since ${\mathbb {P} }^{2k+1}{\mathbb {C} }\,$ is simply connected, such a structure has to be unique.
• Grassmannian $Gr(2,4)\,,$ e.t.c.

See also

• Metaplectic group
• Symplectic frame bundle
• Symplectic group
• Symplectic spinor bundle

Notes

43 year old Petroleum Engineer Harry from Deep River, usually spends time with hobbies and interests like renting movies, property developers in singapore new condominium and vehicle racing. Constantly enjoys going to destinations like Camino Real de Tierra Adentro.

Books

• Many property agents need to declare for the PIC grant in Singapore. However, not all of them know find out how to do the correct process for getting this PIC scheme from the IRAS. There are a number of steps that you need to do before your software can be approved.
  
  Naturally, you will have to pay a safety deposit and that is usually one month rent for annually of the settlement. That is the place your good religion deposit will likely be taken into account and will kind part or all of your security deposit. Anticipate to have a proportionate amount deducted out of your deposit if something is discovered to be damaged if you move out. It's best to you'll want to test the inventory drawn up by the owner, which can detail all objects in the property and their condition. If you happen to fail to notice any harm not already mentioned within the inventory before transferring in, you danger having to pay for it yourself.
  
  In case you are in search of an actual estate or Singapore property agent on-line, you simply should belief your intuition. It's because you do not know which agent is nice and which agent will not be. Carry out research on several brokers by looking out the internet. As soon as if you end up positive that a selected agent is dependable and reliable, you can choose to utilize his partnerise in finding you a home in Singapore. Most of the time, a property agent is taken into account to be good if he or she locations the contact data on his website. This may mean that the agent does not mind you calling them and asking them any questions relating to new properties in singapore in Singapore. After chatting with them you too can see them in their office after taking an appointment.
  
  Have handed an trade examination i.e Widespread Examination for House Brokers (CEHA) or Actual Property Agency (REA) examination, or equal; Exclusive brokers are extra keen to share listing information thus making certain the widest doable coverage inside the real estate community via Multiple Listings and Networking. Accepting a severe provide is simpler since your agent is totally conscious of all advertising activity related with your property. This reduces your having to check with a number of agents for some other offers. Price control is easily achieved. Paint work in good restore-discuss with your Property Marketing consultant if main works are still to be done. Softening in residential property prices proceed, led by 2.8 per cent decline within the index for Remainder of Central Region
  
  Once you place down the one per cent choice price to carry down a non-public property, it's important to accept its situation as it is whenever you move in – faulty air-con, choked rest room and all. Get round this by asking your agent to incorporate a ultimate inspection clause within the possibility-to-buy letter. HDB flat patrons routinely take pleasure in this security net. "There's a ultimate inspection of the property two days before the completion of all HDB transactions. If the air-con is defective, you can request the seller to repair it," says Kelvin.
  
  15.6.1 As the agent is an intermediary, generally, as soon as the principal and third party are introduced right into a contractual relationship, the agent drops out of the image, subject to any problems with remuneration or indemnification that he could have against the principal, and extra exceptionally, against the third occasion. Generally, agents are entitled to be indemnified for all liabilities reasonably incurred within the execution of the brokers´ authority.
  
  To achieve the very best outcomes, you must be always updated on market situations, including past transaction information and reliable projections. You could review and examine comparable homes that are currently available in the market, especially these which have been sold or not bought up to now six months. You'll be able to see a pattern of such report by clicking here It's essential to defend yourself in opposition to unscrupulous patrons. They are often very skilled in using highly unethical and manipulative techniques to try and lure you into a lure. That you must also protect your self, your loved ones, and personal belongings as you'll be serving many strangers in your home. Sign a listing itemizing of all of the objects provided by the proprietor, together with their situation. HSR Prime Recruiter 2010