fix some details in the documentation

src/sage/graphs/connectivity.pyx

@@ -26,7 +26,7 @@ Here is what the module can do:
     :meth:`is_cut_edge` | Check whether the input edge is a cut-edge or a bridge.
     :meth:`is_edge_cut` | Check whether the input edges form an edge cut.
     :meth:`is_cut_vertex` | Check whether the input vertex is a cut-vertex.
-    :meth:`is_vertex_cut` | Check whether ``cut`` is a vertex cut of ``G``.
+    :meth:`is_vertex_cut` | Check whether the input vertices form a vertex cut.
     :meth:`edge_connectivity` | Return the edge connectivity of the graph.
     :meth:`vertex_connectivity` | Return the vertex connectivity of the graph.
 
@@ -974,7 +974,7 @@ def is_cut_edge(G, u, v=None, label=None):
 
 def is_vertex_cut(G, cut, weak=False):
     r"""
-    Check whether ``cut`` is a vertex cut of ``G``.
+    Check whether the input vertices form a vertex cut.
 
     A set of vertices is a vertex cut if its removal from the (di)graph
     increases the number of (strongly) connected components. This function works
@@ -984,7 +984,7 @@ def is_vertex_cut(G, cut, weak=False):
 
     - ``G`` -- a Sage (Di)Graph
 
-    - ``cut`` -- an iterable container of vertices
+    - ``cut`` -- a set of vertices
 
     - ``weak`` -- boolean (default: ``False``); whether the connectivity of
       directed graphs is to be taken in the weak sense, that is ignoring edges

src/sage/graphs/generic_graph.py

@@ -246,7 +246,7 @@
     :meth:`~GenericGraph.is_cut_edge` | Check whether the input edge is a cut-edge or a bridge.
     :meth:`~GenericGraph.`is_edge_cut` | Check whether the input edges form an edge cut.
     :meth:`~GenericGraph.is_cut_vertex` | Check whether the input vertex is a cut-vertex.
-    :meth:`~GenericGraph.is_vertex_cut` | Check whether ``cut`` is a vertex cut of ``G``.
+    :meth:`~GenericGraph.is_vertex_cut` | Check whether the input vertices form a vertex cut.
     :meth:`~GenericGraph.edge_cut` | Return a minimum edge cut between vertices `s` and `t`
     :meth:`~GenericGraph.vertex_cut` | Return a minimum vertex cut between non-adjacent vertices `s` and `t`
     :meth:`~GenericGraph.flow` | Return a maximum flow in the graph from ``x`` to ``y``