A remark on the norm of a formal group over \(\mathbb{Z}_p\) (Q1764325)

Let \(p\) be an odd prime and \(h\geq 2\). The author studies the formal group \(F\) over \(\mathbb Z_p\) of Honda type \(p+X^p\). Let \(k_n\) be the extension of \(\mathbb Q_p\) by means of the \(p^n\)th roots of unity and \(\mathfrak m_n\) the corresponding prime ideal. The author computes the index of the norm group \(N_{k_{n+1}/k_n}F(\mathfrak m_{n+1})\) in \(F(\mathfrak m_n)\).