__ : description: ket1 __ ket2 the infix operator for ket label space merge merge the labels of the two kets, with a space in between, and multiply their coefficients examples: -- "week" + " " + "day": |week> __ |day> |week day> -- an abstract example showing the coefficient multiplication: 3|one> __ 5|two> 15|one two> see also: + , - , _ , :_ , .Home