The letter contains some calculations on irreducible group representations.

Kemmer replies to a letter by Pauli. He writes on calculations on the regular representation of the Abel group and about irreducibility of this representation.

Kemmer rejects an assumption made by Pauli.

Continuation of the letters of 8/9 May.

Salam makes some corrections to his letter of 13 February 1957.

This reply to Pauli's letter is about the irreducibility of the n- group representation.

Continuation of the letter of 8 May, Kemmer makes more remarks about the relation of his representation of the wave equation to de Boglie's.