Suppose an integer optimization problem in which only one of two of the following restrictions must be met. (attention, if one is met, the other is not).

x1+x210

x1+x220

Which of the alternatives below linearly model this situation? (There can be more then one answer)

1)

x1+x210y1

x1+x220y2

y1y2=0

y1 and y2{0,1}

2)

x1+x210+M y1

x1+x220+M y2

y1+y2=1

y1 e y2{0,1}

3)

x1+x210+M y1

x1+x220+M(1y1)

y1{0,1}

4)

x1+x210y1

x1+x220y2

y1+y2=1

y1 e y2{0,1}

5)

x1+x210y1

x1+x220(1y1)

y1{0,1}