improving definition of supergreedy

Author: Sandstorm831

src/sage/combinat/posets/linear_extensions.py

@@ -256,14 +256,14 @@ def is_supergreedy(self):
         r"""
         Return ``True`` if the linear extension is supergreedy.
 
-        A linear extension `[x_1,x_2,...,x_t]` of a finite ordered
-        set `P=(P, <)` is *super greedy* if it can be obtained using
-        the following procedure: Choose `x_1` to be a minimal
-        element of `P`; suppose `x_1,...,x_i` have been chosen;
-        define `p(x)` to be the largest `j\leq i` such that `x_j<x`
-        if such a `j` exists and 0 otherwise; choose `x_{i+1}`
-        to be a minimal element of `P-\{x_1,...,x_i\}` which
-        maximizes `p`.
+        A linear extension of a Poset `P` with elements `\{_1,x_2,...,x_t\}`
+        is *super greedy*, if it can be obtained using the following
+        algorithm: Choose `x_1` to be a minimal element of `P`;
+        suppose `X = \{x_1,...,x_i\}` have been chosen; let `M` be
+        the set of minimal elements of `P/X`. If there is an element
+        of `M` which covers an element `x_j` in `X`, then let `x_{i+1}`
+        be one of these such that `j` is maximal; otherwise, choose `x_{i+1}
+        to be any element of `M`.
 
         Informally, a linear extension is supergreedy if it "always
         goes up and receedes the least"; in other words, supergreedy