[ \Phi^+(t) = G(t) , \Phi^-(t) + g(t), ]
[ \Phi^\pm(t_0) = \pm \frac12 \phi(t_0) + \frac12\pi i , \textP.V. \int_\Gamma \frac\phi(t)t-t_0 , dt, ] [ \Phi^+(t) = G(t) , \Phi^-(t) + g(t),
where P.V. denotes the Cauchy principal value. The singular integral operator The singular integral operator [ a(t) \phi(t) +
[ a(t) \phi(t) + \fracb(t)\pi i , \textP.V. \int_\Gamma \frac\phi(\tau)\tau-t , d\tau = f(t), \quad t \in \Gamma, ] \tau) \phi(\tau) d\tau = f(t)
with given Hölder-continuous ( G(t) \neq 0 ) and ( g(t) ). The of the problem is
[ \Phi(z) = \frac12\pi i \int_\Gamma \frac\phi(\tau)\tau-z , d\tau, ]
This becomes a Riemann–Hilbert problem with ( G(t) = \fraca(t)-b(t)a(t)+b(t) ). Solvability and number of linearly independent solutions depend on the index. [ a(t) \phi(t) + \fracb(t)\pi i \int_\Gamma \frac\phi(\tau)\tau-t d\tau + \int_\Gamma k(t,\tau) \phi(\tau) d\tau = f(t), ]