196 INDEX OF NOTATION

Rp+1, real rational functions of degree p+1

with only real critical points, 135

RP≥0,

A

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

WrR, real Wronski map, 11

XA, toric variety, 29

XA, toric degeneration, 40

xa,

monomial, 3

XαF•, Schubert variety, 117

XαF•,

◦

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

YA

+

, 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