Spin network

Spin networks (english spin network) were invented in 1971 by Roger Penrose and provide a combinatorial approach to space-time of general relativity dar.

This mathematical formalism was rediscovered in the Loop Quantum Gravity ( LQG, and loop quantum gravity ) and expanded. Spin networks have the Wilson loops replaced as mathematical orthonormal basis of the LQG Hilbert space.

They are schematically of nodes and lines and just represent the quantized space that the LQG then can alone be derived from the concepts of general relativity and quantum mechanics. Rearrangements in spin- network then define a local notion of time and result in the spin- foam.