The following pdf written almost 5 years ago demonstrates the hidden significance of Euler's identity that is crucial for establishing the mathematics of Hadamard matrices.
The following pdf file written almost 5 years ago shows the mathematical connections between Hadamard matrices and Pauli=Dirac matrices.
The following pdf file written almost 5 years ago gives a more detailed descriptions for the mathematics of Hadamard matrices.
The attached pdf file is a short paper written 5 years ago on the mathematics of spacetime quantization.