196 INDEX OF NOTATION Rp+1, real rational functions of degree p+1 with only real critical points, 135 RPA ≥0 , nonnegative orthant, 83 RPn, real projective space, 2 σm,p, degree of real Wronski map, 10 σ(ω), signature of a foldable triangulation, 85 σ(P ), sign-imbalance of poset P , 92 sign(w), sign of permutation w, 93 SN , symmetric group, 149 Sn, n-dimensional sphere, 80 Sω, regular subdivision, 42 St(p, m+p), Stiefel manifold, 96 StR(2, p+1), real Stiefel manifold, 134 T, nonzero complex numbers C∗, 1, 3, 26 TR, nonzero real numbers R∗, 1, 65 TxX, tangent space of X at x, 11 ubcD(C), number of unbounded components of curve C, 67 VD(g1, . . . , gm), common zeroes of gi in D, 67 var(c), variation in a sequence c, 14 var(F, a), variation in a sequence F of polynomials at a ∈ R, 14 Vμ, highest weight module, 153 volume(Δ), volume of polytope Δ, 3, 26 Wκ,c(x), Wronski polynomial, 85 Wr, Wronski map, 5 Wr(f1,. . . , fm), Wronskian of f1,. . . , fm, 5 Wr R , real Wronski map, 11 XA, toric variety, 29 XA, toric degeneration, 40 xa, monomial, 3 XαF•, Schubert variety, 117 X◦F•, α Schubert cell, 126 X(l, n), Khovanskii number, 4, 49, 50 XR(l, n), Khovanskii number, 50 XwB, Schubert variety, 179 YA, real part of toric variety XA, 79 Y + A , spherical toric variety, 80 YA,, positive part of toric variety XA, 88 Z, integers, 1 ZA, integer aﬃne span of A, 28 Zn, integer lattice, 2 [Zn : ZA], lattice index, 28

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