We obtain a duality between certain category of finite MTL-algebras and the category of finite labeled trees. In addition we prove that certain poset products of MTL-algebras are essentialy sheaves of MTL-chains over Alexandrov spaces. Finally we give a concrete description for the studied poset products in terms of direct products and ordinal sums of finite MTL-algebras.Proof. Let f be an injective morphism of MTL-algebras, then f (x) = 1 = f (1) implies x = 1. On the other hand, let us assume that f (thus by general properties of the residual it follows that f (a) → f (b) = 1 and f (b) → f (a) = 1 so f (a → b) = 1 and f (b → a) = 1. From the assumption we get that a → b = 1 and b → a = 1, thus a ≤ b and b ≤ a. Hence, a = b so f is injective.Lemma 4. Let f : A → B be a morphism of finite MTL-chains. If A is archimedean then B = 1 or f is injective.Proof. Since A is archimedean, by (ii) of Corollary 1 we get that if is also simple so K f = A or K f = {1}. In the first case, we get that f (a) = 1 for every a ∈ A, so in particular f (0) = 0 = 1, hence B = 1. In the last case, it follows that f (a) = 1 implies a = 1, so by Lemma 3 f is injective.