Wavy Lie algebra and its Koszul dual
1 Wavy Lie algebra
Let
be a Lie group. It is possible to introduce the structure of a Lie group on
.
In fact:
and the structure of the group is introduced by pointwise multiplication. Consider the corresponding Lie superalgebra:
We can interpret
as the algebra of maps from
to
;
therefore the elements of
are
-valued functions
of an odd
parameter
.
It is possible to extend
by an extra odd element
with the following
commutation relations:
We will call this extended algebra
.
2 Koszul dual to wavy Lie algebra
Let us consider the universal enveloping
and look at it as a quadratic-linear
algebra. The dual algebra is a differential algebra; it has a nonzero differential because the
original algebra was quadratic-linear; the differential corresponds to the commutator.
We will call it
:
This is generated by the linear space:
.
Let
be the basis of
as a linear space.
Then
is generated
by odd elements
and even elements
:
As a dual to a non-homogeneous quadratic-linear algebra,
the supercommutative algebra
comes with the differential:
But since
was actually a DLA, the differential being
,
the dual map
defines the second differential on
:
These two differentials commute:
The total differential is called
:
Schematically:
Notice that:
The cohomology of
is
; this can be proven using the homotopy operator: