Given a real constant , we let denote the solution to the ordinary differential equation
(1.1) |
Setting , we clearly get and satisfies , with initial condition .
PEL is the class of functions that can be described by
where can be any polynomial and the left superscript denotes tetration.
The complexity class PEL is the class of languages recognisable by a TM in time , where is in PEL and is the bit-length of the input. Equivalently, PEL is the class of languages recognisable by a TM working on a tape of size , where is in PEL.
PEL can therefore also be described as either PEL-TIME or PEL-SPACE.
Two factors of automorphy and are called equivalent if there is a holomorphic function satisfying
Two summands of automorphy are called equivalent if the induced factors of automorphy are equivalent.
A map such that
is said to have the antipodal property.
A reduction between two chain complexes and , denoted by , is a triple where and are chain complex morphisms, is a family of module morphism, and the following properties are satisfied:
;
;
; ; .
A Clifford geometric algebra is defined by the associative geometric product of elements of a quadratic vector space , their linear combination and closure. includes the field of real numbers and the vector space as subspaces. The geometric product of two vectors is defined as
(1) |
where indicates the standard inner product and the bivector indicates Grassmann’s antisymmetric outer product. can be geometrically interpreted as the oriented parallelogram area spanned by the vectors and . Geometric algebras are graded, with grades (subspace dimensions) ranging from zero (scalars) to (pseudoscalars, -volumes).
Given , is the set of all s.t.
The set of formal power series with coefficients in a semiring endowed with the following sum and Cauchy product:
is a semiring denoted . If is complete, is complete. A series with a finite support is called a polynomial, and a monomial if there is only one element in the series. The greatest lower bound of series is given by :
Under conditions , and there exists a Radon measure and a measurable function such that
(4) |
In particular, and is the (signed) density .
Let be a Lie algebra whose centre is and let .We say that is of Heisenberg-type (or simply -type) if
and there exists an inner product on with such that for any , the map given by
for , is an orthogonal map whenever . An -type group is a connected and simply connected Lie group whose Lie algebra is of -type.