Expanding a determinant

An alternative procedure first proposed by Moffitt79 is to expand a determinant D(iif2.. . is) of non-orthogonal spin orbitals directly in terms of determinants composed of orthogonal orbitals. Let us denote the non-orthogonal spin orbitals by y, and the orthogonalized counterparts by Each l/t may then be written as a linear combination... 

The process can be generalised by taking more than two rows and columns, and it is also possible to expand a determinant in minors of dijfferent orders, provided the sum of the orders is equal to the order of the determinant. 

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