fix error in docstring and readme

Author: stecrotti

README.md

@@ -34,7 +34,7 @@ FactorGraph{Int64} with 5 variables, 3 factors, and 6 edges
 
 ### Graph navigation 
 Given a factor graph with $N$ variables and $M$ factors, variables are indexed by $i\in\{1,\ldots,N\}$, factors are indexed by $a\in\{1,\ldots,M\}$.
-Properties of a vertex can be queried by wrapping the vertex index in a `variable` or `factor`. For example, the list of neighbors of variable $i=2$ is found by
+Properties of a vertex can be queried by wrapping the vertex index in a `v_vertex` or `f_vertex`. For example, the list of neighbors of variable $i=2$ is found by
 ```julia
 julia> ∂i = neighbors(g, variable(2));
 
@@ -59,7 +59,7 @@ julia> collect(ea)
 Querying properties of a vertex without specifying whether it's a variable or a factor will throw an error
 ```julia
 julia> outedges(g, 3)
-ERROR: ArgumentError: Properties of a vertex of an `AbstractFactorGraph` such as degree, neighbors, etc. cannot be accessed by an integer. Use a `variable` or `factor` wrapper instead.
+ERROR: ArgumentError: Properties of a vertex of an `AbstractFactorGraph` such as degree, neighbors, etc. cannot be accessed by an integer. Use a `v_vertex` or `f_vertex` wrapper instead.
 ```
 
 ## See also

src/factorgraph.jl

@@ -5,7 +5,7 @@ const VariableVertex = Right
     FactorGraphVertex
 
 A type to represent a vertex in a bipartite graph, to be passed as an argument to [`neighbors`](@ref), [`inedges`](@ref), [`outedges`](@ref), see examples therein.
-It is recommended to use the [`v_vertex`](@ref) and [`fvertex`](@ref) constructors.
+It is recommended to use the [`v_vertex`](@ref) and [`f_vertex`](@ref) constructors.
 """
 const FactorGraphVertex = BipartiteGraphVertex
 
@@ -284,7 +284,7 @@ end
 for method in [:(IndexedGraphs.degree), :(IndexedGraphs.inedges), :(IndexedGraphs.outedges), :(IndexedGraphs.neighbors), :(edge_indices)]
     @eval begin
         function $method(::AbstractFactorGraph, ::Integer)
-            return throw(ArgumentError("Properties of a vertex of an `AbstractFactorGraph` such as degree, neighbors, etc. cannot be accessed by an integer. Use a `v_vertex` or `fvertex` wrapper instead.\n"))
+            return throw(ArgumentError("Properties of a vertex of an `AbstractFactorGraph` such as degree, neighbors, etc. cannot be accessed by an integer. Use a `v_vertex` or `f_vertex` wrapper instead.\n"))
         end
     end
 end