Unitary Shimura varieties of signature (1, n), 2 ≤ n ≤ 7, at every standard maximal parahoric level (E/ℚp unramified, p > 2). The lattice view puts every EKOR stratum at Muller's coordinates (c+, c−): the basic locus is the L-shaped pair of strips, and the non-basic Newton strata are the anti-diagonals of the remaining box. The closure-diagram view is the atlas's own picture, whose rows are those anti-diagonals.
h is Muller's index for the level. Columns B … O give Newton-stratum dimensions; – means the class does not occur.
Conventions as in the atlas: d = n + 1, affine type Ãd−1, μ = e1, σ+(si) = s−i (odd d and split even d), σ−(si) = s1−i (nonsplit even d). All data are recomputed in this page from Part II, §§2–4 of the atlas (arcs A, B, supports C(x, y) = A[1, x] ∪ B[1, y], the δ±-orbit test (8), r = d − k (7)) and agree with all 352 entries of its tables. Muller's coordinates come from the reflection i ↦ −i of ℤ/dℤ, which turns his Frobenius j ↦ −j − (1−ε)/2 into the atlas's σ± and his blocks with their initial segments into the arcs with their prefixes: c− runs along the arc of length h, c+ along the other one. In these coordinates the atlas's basicness test is exactly Muller's: 2c+ ≤ ℓ+ − 1 or 2c− ≤ ℓ− − 1. The closure order is the componentwise order, so the closure of a stratum is the box below and to the left of it.