玻色弦理論understood as the induced metric from the embedding, but as an independent dynamical field. G {\displaystyle G} is the metric on the target spacetime,
模式匹配| Tree (Black, Tree (Red, a, x, Tree (Red, b, y, c)), z, d) | Tree (Black, a, x, Tree (Red, Tree (Red, b, y, c), z, d)) | Tree (Black, a, x, Tree (Red