Figure 2

Boolean functions and operations among them. a) Boolean functions with one input. Functions with a dashed line are not considered because the output is independent of the input. b) Boolean functions with two inputs. Functions with a dashed line are not considered because the output is independent of at least one input. c) An example showing the removal of the right marker (B) from function (2,2), which can be either result into function (1,0) or (1,1). Since function (1,0) is excluded then the function (1,1) is always chosen. d) Same example but removing the left marker (A). e) All mappings from (2,b) to (1,b’) following removal of the right (B) marker. f) All mappings from (2,b) to (1,b’) following removal of the left marker. e) All mappings from (1,b) to (2,b’) following the addition of a marker. For simplicity, we have chosen the reverse of the right-marker removal (panel e) as the mapping for the marker addition.