We verify Katzarkov-Kontsevich-Pantev conjecture for Landau-Ginzburg models of smooth Fano threefolds.P {x},{y},{t} : quadratic term (x + t)(y + t); P {x},{t},{y,z} : quadratic term z(x + t); P {y},{z},{x,t} : quadratic term z(x + t).By Corollary 1.12.2, we have D −2 P = 0 for every P ∈ Σ, so that [f −1 (−2)] = 2. Thus, we see that (♥) in Main Theorem holds in this case, since h 1,2 (X) = 1.1.13. Curves on singular quartic surfaces. We will prove (♦) in Main Theorem by computing the intersections form of the curves C 1 , . . . , C r on a general surface in the pencil S. To do this, let k = C(λ), let S k be the quartic surface in P 3 k that is given by (1.4.1), and let ν : S k → S k be the minimal resolution of singularities of the surface S k .Lemma 1.13.1. Suppose that λ is a general element of C. Then the surface S λ is singular, and it has du Val singularities. Let M be the r × r matrix with entries M ij ∈ Q that are given by M ij = C i • C j , where C i • C j is the intersection of the curves C i and C j on the surface S λ . Then the right hand side of (♦) is equal toProof. Let F be a general fiber of the morphism f. Then H 2 (F, R) ∼ = Z 22 , since F is a smooth K3 surface. This easily implies the required assertion.3 x2 3 ž3 −3 ť5 3 x3 ž2 3 +6 ť6 3 x2 3 ž3 −3 ť6 3 x3 3 −3 ť6 3 x3 ž2 3 +3 ť6 3 x3 3 ž3 − ť6 3 x4 3 −3 ť6 3 x2 3