These functions all lets the user query whether each node is of a certain type. All of the functions returns a logical vector indicating whether the node is of the type in question. Do note that the types are not mutually exclusive and that nodes can thus be of multiple types.

```
node_is_cut()
node_is_root()
node_is_leaf()
node_is_sink()
node_is_source()
node_is_isolated()
node_is_universal(mode = "out")
node_is_simplical(mode = "out")
node_is_center(mode = "out")
node_is_adjacent(to, mode = "all", include_to = TRUE)
node_is_keyplayer(k, p = 0, tol = 1e-04, maxsec = 120, roundsec = 30)
node_is_connected(nodes, mode = "all", any = FALSE)
```

- mode
The way edges should be followed in the case of directed graphs.

- to
The nodes to test for adjacency to

- include_to
Should the nodes in

`to`

be marked as adjacent as well- k
The number of keyplayers to identify

- p
The probability to accept a lesser state

- tol
Optimisation tolerance, below which the optimisation will stop

- maxsec
The total computation budget for the optimization, in seconds

- roundsec
Number of seconds in between synchronizing workers' answer

- nodes
The set of nodes to test connectivity to. Can be a list to use different sets for different nodes. If a list it will be recycled as necessary.

- any
Logical. If

`TRUE`

the node only needs to be connected to a single node in the set for it to return`TRUE`

A logical vector of the same length as the number of nodes in the graph.

`node_is_cut()`

: is the node a cut node (articaultion node)`node_is_root()`

: is the node a root in a tree`node_is_leaf()`

: is the node a leaf in a tree`node_is_sink()`

: does the node only have incomming edges`node_is_source()`

: does the node only have outgoing edges`node_is_isolated()`

: is the node unconnected`node_is_universal()`

: is the node connected to all other nodes in the graph`node_is_simplical()`

: are all the neighbors of the node connected`node_is_center()`

: does the node have the minimal eccentricity in the graph`node_is_adjacent()`

: is a node adjacent to any of the nodes given in`to`

`node_is_keyplayer()`

: Is a node part of the keyplayers in the graph (`influenceR`

)`node_is_connected()`

: Is a node connected to all (or any) nodes in a set

```
# Find the root and leafs in a tree
create_tree(40, 2) %>%
mutate(root = node_is_root(), leaf = node_is_leaf())
#> # A tbl_graph: 40 nodes and 39 edges
#> #
#> # A rooted tree
#> #
#> # Node Data: 40 × 2 (active)
#> root leaf
#> <lgl> <lgl>
#> 1 TRUE FALSE
#> 2 FALSE FALSE
#> 3 FALSE FALSE
#> 4 FALSE FALSE
#> 5 FALSE FALSE
#> 6 FALSE FALSE
#> 7 FALSE FALSE
#> 8 FALSE FALSE
#> 9 FALSE FALSE
#> 10 FALSE FALSE
#> # ℹ 30 more rows
#> #
#> # Edge Data: 39 × 2
#> from to
#> <int> <int>
#> 1 1 2
#> 2 1 3
#> 3 2 4
#> # ℹ 36 more rows
```