Unified description of the non-singlet spin dependent structure function $g_1$ incorporating Altarelli-Parisi evolution and the double logarithmic $l{n}^2(1\mathrm{/}x)$ effects at low $x$

A unified equation for the non-singlet spin dependent structure function $g_1^{ns}(x,Q^2)$ which incorporates the complete leading order Altarelli-Parisi evolution at finite $x$ and double logarithmic $l{n}^2(1\mathrm{/}x)$ effects at $x\to 0$ is formulated. The solution of this equation reasonably agrees with the recent data obtained by the Spin Muon Collaboration.