What does it mean for two binary trees to be isomorphic?

Question

What does it mean for two binary trees to be isomorphic? I\'ve been looking online and I can\'t seem to find a clear explanation.

As far as I understand, two trees

Answer 1

Following conditions must fulfill to two trees to be isomorphic :
1. Two Tree are isomorphic if and only if they preserve same no of levels and same no of vertices in each level .

2.Two trees are isomorphic if and only if they have same degree spectrum .

3.Two trees are isomorphic if and only if they have same degree of spectrum at each level.

4. Total no of leaf descendant of a vertex and the level number of vertex are both tree tree isomorphic invariant .

IN Simple words :
Two trees are isomorphic if one tree can be obtained from other by performing any number of flips i.e swapping left childrens and right childrens of a number of node .

Example of isomorphic trees:

Ref: 1.http://www14.in.tum.de/konferenzen/Jass03/presentations/eterevsky.pdf 2.http://www.geeksforgeeks.org/tree-isomorphism-problem/