In mathematics and theoretical physics, the Berezinian or superdeterminant is a generalization of the determinant to the case of supermatrices. The name is for Felix Berezin. The Berezinian plays a role analogous to the determinant when considering coordinate changes for integration on a supermanifold.
Definition.
The Berezinian is uniquely determined by two defining properties:
where str("X") denotes the supertrace of "X". Unlike the classical determinant, the Berezinian is defined only for invertible supermatrices.
The simplest case to consider is the Berezinian of a supermatrix with entries in a field "K". Such supermatrices represent linear transformations of a super vector space over "K". A particular even supermatrix is a block matrix of the form
formula_3
Such a matrix is invertible if and only if both "A" and "D" are invertible matrices over "K". The Berezinian of "X" is given by
formula_4
For a motivation of the negative exponent see the substitution formula in the odd case.
More generally, consider matrices with entries in a supercommutative algebra "R". An even supermatrix is then of the form
formula_5
where "A" and "D" have even entries and "B" and "C" have odd entries. Such a matrix is invertible if and only if both "A" and "D" are invertible in the commutative ring "R"0 (the even subalgebra of "R"). In this case the Berezinian is given by
formula_6
or, equivalently, by
formula_7
These formulas are well-defined since we are only taking determinants of matrices whose entries are in the commutative ring "R"0. The matrix
 formula_8
is known as the Schur complement of "A" relative to formula_9
An odd matrix "X" can only be invertible if the number of even dimensions equals the number of odd dimensions. In this case, invertibility of "X" is equivalent to the invertibility of "JX", where
formula_10
Then the Berezinian of "X" is defined as
formula_11
Berezinian module.
The determinant of an endomorphism of a free module "M" can be defined as the induced action on the 1-dimensional highest exterior power of "M". In the supersymmetric case there is no highest exterior power, but there is a still a similar definition of the Berezinian as follows. 
Suppose that "M" is a free module of dimension ("p","q") over "R". Let "A" be the (super)symmetric algebra "S"*("M"*) of the dual "M"* of "M". Then an automorphism of "M" acts on the ext module
formula_18
as multiplication by the Berezinian.