Unitary

If yes–no questions are CPs containing a null yes–no question operator (a null counterpart of whether) in spec-CP, we can arrive at a unitary characterisation of questions as CPs with an interrogative specifier.

a unitary authority

a unitary state

The eigenvectors of an orthogonal or unitary operator, corresponding to different eigenvalues, are orthogonal.

In essence we are looking for some way to average the individual unitary matrices Uₖ. But a linear combination of unitary matrices does not remain unitary.

We then repeat the same procedure to the (d − 1) × (d − 1) block unitary matrix using (d − 2) two-level unitary matrices.

Outside the metropolitan areas most councils (English and Welsh counties, London boroughs, Scottish and Welsh unitaries, and Northern Ireland districts) are now elected en bloc every four years.

1980, Michael Reed, Barry Simon, Methods of Modern Mathematical Physics, Volume 1: Functional Analysis, Revised and Expanded Edition page 243, Since ergodicity and mixing are expressible in terms of the induced Koopman unitaries they are not additional invariants.