Cohen–Hewitt factorization theorem

In mathematics, the Cohen–Hewitt factorization theorem states that if V is a left module over a Banach algebra B with a left approximate unit ( u i ) i ∈ I , then an element v of V can be factorized as a product v = b w (for some b ∈ B and w ∈ V ) whenever lim i ∈ I u i v = v . The theorem was introduced by Paul Cohen (1959) and Edwin Hewitt (1964).