Split operator and inverted triangle operator, are they symbols with shapes? . That is, the quantity behind the inverted triangle is operated as follows: it means that the derivative of the function in each orthogonal direction is multiplied by the unit vector in each direction.

Wedge operator is used to refer to gradient operator in mathematics. It is also used to refer to connections in differential geometry (in a broader sense, it can be regarded as gradient operators). It was put forward by Hamilton. For example, the electric field intensity e =-u means that the electric field intensity e is the negative gradient of the potential u, which is a vector, and the direction points to the direction where the potential drops fastest (the gradient is increasing, so the negative sign indicates the decline).