further fixes to supergreedy docstring

Author: dimpase

src/sage/combinat/posets/linear_extensions.py

@@ -257,16 +257,16 @@ def is_supergreedy(self):
         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
+        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}`
+        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`..
+        maximizes `p`.
 
-        Informally said a linear extension is supergreedy if it "always
-        goes up and receedes the least" loosely speaking, supergreedy
+        Informally, a linear extension is supergreedy if it "always
+        goes up and receedes the least"; in other words, supergreedy
         linear extensions are depth-first linear extensions.
 
         EXAMPLES::