fermionQ

◼ fermionQ[c] returns True if c is a fermionic operator.

◼ Operators are usually declared to be fermionic using snegfermionoperators.

◼ For fermionic operators, Pauli rule is imposed and automatic reordering is performed. In all other respects, they behave as general operators (see operatorQ).

◼ See also operatorQ.

Further examples

Load sneg

<< sneg`sneg`;

Let c be a fermionic operator

snegfermionoperators[c]

Check that c is recognized as fermionic operator

fermionQ[c]
operatorQ[c]
c[CR, UP]
listfermionoperators

Operators can be manually defined to be fermionic. In this case, pretty printing is disabled and the operators are not added to listfermionoperators.

fermionQ[d] = True
operatorQ[d]
d[CR, UP]
listfermionoperators

Pauli rule

nc[c[], c[]] == 0
nc[c[CR], c[CR]] == 0
nc[c[AN], c[AN]] == 0
nc[c[t], c[t]] == 0

Automatic reordering

nc[c[AN, UP], c[CR, UP]]