produced by the main connective is true for the case 13 7 Large button 1 Man. _Manual pulse_ Input: causes the Pulse _button_ calc. to go to the next line of a truth table 14 7 11-position 1 _kⱼ_ _Connective check_ Output: glows when dial switch _switch and light_ any specified connective is true 15 7 13-position 1 TT “_Truth-table-row-_ Input: causes the dial switch Row _stop_” _switch_ calc. to stop on Stop last row of the the truth table 16 Be- Continuous 1 — _Timing control_ Input: controls the tween dial knob _knob_ speed at which 6 & 7 and button the calculator scans rows of the truth table Some of the words appearing in this table need to be defined. _Connective_ here means “AND,” “OR,” “IF ··· THEN,” “IF AND ONLY IF.” Only these four connectives appear on the machine; others when needed can be constructed from these. The symbols used for these connectives in mathematical logic are ∧, ∨, ▲, ▼. These signs serve as labels for the connective switch points. In this machine, when there is a connective between two statements, the statement that comes before is called the _antecedent_ and the statement that comes after is called the _consequent_. HOW INFORMATION GOES INTO THE MACHINE Of the 16 units 13 are input units. They control the setup of the machine so that it can solve a problem. Of the 13 input units, those that have the most to do with taking in the problem are shown in Table 12. Table 12 Name of KIND OF UNIT SWITCHES MARK SWITCH SWITCH SETTINGS