The equation of state for a neutron star is still not known.

The above equation is known as the phase matching condition.

This is useful if the equation of state is known.

Maxwell's equations were completely known by the latter part of the nineteenth century.

This requires an additional equation, known as a closure relation.

This equation is known as the ideal gas law.

The uncertainty in the value reflects the fact that the equations of state for extremely dense matter are not well known.

These equations are known as "equations of state" with respect to the internal energy.

An equation that address stereochemistry in aliphatic systems is also known.

The latter equation is sometimes known as Hopkinson's law.