In graph theory, the Y-Δ transform means replacing a Y subgraph of a graph with the equivalent Δ subgraph. The transform preserves the number of edges in a graph, but not the number of vertices or the number of cycles. Two graphs are said to be Y-Δ equivalent if one can be obtained from the other by a series of Y-Δ transforms in either direction. For example, the Petersen graphs are a Y-Δ equivalence class.

Δ-लोड से Y-लोड में परिवर्तन के समीकरण
तीन-फेजी परिपथ में Δ-लोड को Y-लोड में बदलने का समीकरण
Y-लोड से Δ-लोड में परिवर्तन के समीकरण
ग्राफ सिद्धान्त (Graph theory)