Step-by-step derivation
S001 · implies
Before
n=6;raw edges=[[0, 2], [0, 3], [0, 4], [0, 5], [1, 3]]
After
canonical edges=[[0, 2], [0, 3], [0, 4], [0, 5], [1, 3]]
Conditions: none
Validate every simple undirected edge for typed distinct endpoints.Sort endpoints and count reversed or repeated edges once;do not infer adjacency from a drawing.
Step identifiers and dependencies
Rule: simple_graph_edge_normalization · Uses: G001
S002 · implies
Before
phase=original;vertex=0;all edges=[[0, 2], [0, 3], [0, 4], [0, 5], [1, 3]]
After
neighbors=[2, 3, 4, 5];degree=4
Conditions: none
Scan all canonical edges.An incident edge contributes its other endpoint as a distinct neighbor.Keep original vertex labels.
Step identifiers and dependencies
Rule: complete_graph_neighbor_inventory · Uses: G001, S001
S003 · implies
Before
phase=original;vertex=1;all edges=[[0, 2], [0, 3], [0, 4], [0, 5], [1, 3]]
After
neighbors=[3];degree=1
Conditions: none
Scan all canonical edges.An incident edge contributes its other endpoint as a distinct neighbor.Keep original vertex labels.
Step identifiers and dependencies
Rule: complete_graph_neighbor_inventory · Uses: G001, S002
S004 · implies
Before
phase=original;vertex=2;all edges=[[0, 2], [0, 3], [0, 4], [0, 5], [1, 3]]
After
neighbors=[0];degree=1
Conditions: none
Scan all canonical edges.An incident edge contributes its other endpoint as a distinct neighbor.Keep original vertex labels.
Step identifiers and dependencies
Rule: complete_graph_neighbor_inventory · Uses: G001, S003
S005 · implies
Before
phase=original;vertex=3;all edges=[[0, 2], [0, 3], [0, 4], [0, 5], [1, 3]]
After
neighbors=[0, 1];degree=2
Conditions: none
Scan all canonical edges.An incident edge contributes its other endpoint as a distinct neighbor.Keep original vertex labels.
Step identifiers and dependencies
Rule: complete_graph_neighbor_inventory · Uses: G001, S004
S006 · implies
Before
phase=original;vertex=4;all edges=[[0, 2], [0, 3], [0, 4], [0, 5], [1, 3]]
After
neighbors=[0];degree=1
Conditions: none
Scan all canonical edges.An incident edge contributes its other endpoint as a distinct neighbor.Keep original vertex labels.
Step identifiers and dependencies
Rule: complete_graph_neighbor_inventory · Uses: G001, S005
S007 · implies
Before
phase=original;vertex=5;all edges=[[0, 2], [0, 3], [0, 4], [0, 5], [1, 3]]
After
neighbors=[0];degree=1
Conditions: none
Scan all canonical edges.An incident edge contributes its other endpoint as a distinct neighbor.Keep original vertex labels.
Step identifiers and dependencies
Rule: complete_graph_neighbor_inventory · Uses: G001, S006
S008 · implies
Before
phase=original;root=0;depth=0;frontier=[0]
After
next newly reached=[2, 3, 4, 5];component seen=[0, 2, 3, 4, 5]
Conditions: none
Expand along canonical edges only to unseen original labels.A component is complete only when its frontier empties;then start at another unseen vertex.
Step identifiers and dependencies
Rule: tree_complete_reachability_layer · Uses: G001, S007
S009 · implies
Before
phase=original;root=0;depth=1;frontier=[2, 3, 4, 5]
After
next newly reached=[1];component seen=[0, 1, 2, 3, 4, 5]
Conditions: none
Expand along canonical edges only to unseen original labels.A component is complete only when its frontier empties;then start at another unseen vertex.
Step identifiers and dependencies
Rule: tree_complete_reachability_layer · Uses: G001, S008
S010 · implies
Before
phase=original;root=0;depth=2;frontier=[1]
After
next newly reached=[];component seen=[0, 1, 2, 3, 4, 5]
Conditions: none
Expand along canonical edges only to unseen original labels.A component is complete only when its frontier empties;then start at another unseen vertex.
Step identifiers and dependencies
Rule: tree_complete_reachability_layer · Uses: G001, S009
S011 · implies
Before
phase=original;spanning forest=[[0, 2], [0, 3], [0, 4], [0, 5], [1, 3]];all edges=[[0, 2], [0, 3], [0, 4], [0, 5], [1, 3]]
After
nonforest edges=[];cyclic=No
Conditions: none
First-discovery edges form a tree in each reached component.Any remaining edge closes an existing tree path into a cycle.Components were established first;this is not an edge-count-only tree test.
Step identifiers and dependencies
Rule: spanning_forest_cycle_witness · Uses: G001, S010
S012 · implies
Before
phase=original;vertices=[0, 1, 2, 3, 4, 5];components=[[0, 1, 2, 3, 4, 5]];cyclic=No
After
pairwise reachable=Yes;nonempty=Yes;tree=Yes
Conditions: none
A tree must be nonempty,have one component and be acyclic.Pairwise reachability is vacuously true on an empty vertex set,but nonemptiness fails.A singleton with no edges is a tree;its degree0 vertex is not a leaf.
Step identifiers and dependencies
Rule: nonempty_connected_acyclic_tree_gate · Uses: G001, S011
S013 · implies
Before
original tree=Yes;endpoints=[3, 0];typed=[Yes, Yes]
After
path lookup qualified=Yes
Conditions: none
A failed original-tree guard takes precedence.Only for an original tree do endpoint types permit path lookup.A local path's existence does not establish whole-graph treehood.
Step identifiers and dependencies
Rule: tree_path_whole_graph_and_endpoint_guard · Uses: G001, S012
S014 · implies
Before
phase=query;prefix=[3];next=0
After
edge=[0, 3] present;new prefix=[3, 0]
Conditions: none
Each step follows an original edge to a nonrepeated vertex.The simple path between tree vertices is unique;equal endpoints need no edge.
Step identifiers and dependencies
Rule: qualified_tree_path_edge · Uses: G001, S013
S015 · implies
Before
phase=query;start=3;end=0
After
unique path=[3, 0]
Conditions: none
Path uniqueness relies on the earlier original-tree qualification;it is not asserted for a general cyclic graph.
Step identifiers and dependencies
Rule: qualified_tree_path_result · Uses: G001, S014
S016 · calculation
Before
qualified path edge count := sub(2, 1)
After
qualified path edge count = 1
Conditions: none
Substitute the source data exactly in the stated operand order;division requires a nonzero denominator.
Step identifiers and dependencies
Rule: exact_rational_arithmetic · Uses: G001, S015