Theorem: p(V = V_0) = 0 (Murnaghan EOS zero-pressure reference state)

Theorem (Murnaghan-zero-pressure canonical): substituting V = V_0 into p(V) = (K_0/K_0')[(V_0/V)^{K_0'} - 1] gives p = (K_0/K_0')[1 - 1] = 0 identically. Canonical sympy pins: K0, K0p, V, V0 = sp.symbols('K0 K0p V V0', positive=True); p_M…