Published online by Cambridge University Press: 12 March 2014
In this paper we describe the well-founded initial segment of the free Heyting algebra α on finitely many, α, generators. We give a complete classification of initial sublattices of
2 isomorphic to
1 (called ‘low ladders’), and prove that for 2 ≤ α < ω, the height of the well-founded initial segment of
α is ω2.