The <<and...>> function performs a logical conjunction of two or more Boolean values. If all arguments to the function are true, the function will return true. Otherwise, the <<and...>> function will return false.
This function is almost always used as an argument to another function, normally the <<if...>> function. The reason for this is that the value returned is a Boolean value within the SDML and will simply return the text values of “true” or “false,” if not an argument to another function.