Binary variables about jslpsolver HOT 1 OPEN

var problem = [ 
    "max: 21x11 22.5x21 22.5x12 24.5x22 23x13 25.5x23 1500y1 2000y2 3000y3", 
    "1x11 1x21 <= 425", 
    "1x12 1x22 >= 400", 
    "1x13 1x23 >= 750", 
    "1x11 1x12 1x13 >= 550", 
    "1x21 1x22 1x23 >= 450", 
    "1x11 1x21 -425y1 <= 0", 
    "1x12 1x22 -400y2 <= 0", 
    "1x13 1x23 -750y3 <= 0", 
    // I think these are redundant
    "1x11 >= 0", 
    "1x12 >= 0",
    "1x13 >= 0", 
    "1x21 >= 0", 
    "1x22 >= 0", 
    "1x23 >= 0", 
    "int x11", 
    "int x21", 
    "int x12", 
    "int x22", 
    "int x13", 
    "int x23",
    // AKA CHEATING
    "int y1",
    "int y2",
    "int y3",
    "1y1 <= 1",
    "1y2 <= 1",
    "1y3 <= 1"
    ];