Critical point exponents inequalities - The Coopersmith inequolity

LagrangeEuler

The Coopersmith inequolity:
[tex]T=T_c, H\rightarrow 0^+[/tex]

I'm confused by few things. What means [tex]H\rightarrow 0^+[/tex]? And what difference will be if [tex]H\rightarrow 0^-[/tex]? And what means [tex]T=T_c[/tex] if we can't measure [tex]T_c[/tex] in experiments?

Then there is relation [tex]M \sim H^{\frac{1}{\delta}}[/tex]
That means if I understand well that
[tex]\frac{1}{\delta}=\lim_{H\rightarrow 0}\frac{lnM(H)}{lnH}[/tex]
Correct?

LagrangeEuler

Any answer?