Mirror Symmetry — Calabi-Yau

h1,1 ↔ h2,1  |  Candelas–de la Ossa–Green–Parkes 1991
M (original)
W (mirror)
Mirror symmetry is a duality between pairs of Calabi-Yau manifolds M and its mirror W, swapping the Hodge numbers hp,q(M) ↔ hq,p(W). The key exchange is h1,1(M) = h2,1(W) and h2,1(M) = h1,1(W) — counting complex structure deformations vs. Kähler deformations. The quintic threefold (h1,1=1, h2,1=101) mirrors with h1,1=101, h2,1=1. Candelas et al. used mirror symmetry to compute 2875 rational curves of degree 1 on the quintic — matching Clemens' 1986 result — and predicted 609250 conics (degree 2), later verified by algebraic geometers. The visualization shows a 2D projection of a Calabi-Yau slice rotating in parameter space.