isomorphism: \(f:A→B\) which can be "undone" i.e.\(∃g:B→A\), \(g∘f=id_A\) & \(f∘g=id_B\)
in this case, \(A\) & \(B\) are isomorphic.
isomorphism: \(f:A→B\) which can be "undone" i.e.
\(∃g:B→A\), \(g∘f=id_A\) & \(f∘g=id_B\)
in this case, \(A\) & \(B\) are isomorphic.
A≌B means A and B are essentially the same.
In Category Theory, = is in fact mostly ≌.
For example in commutative diagrams.