modify intersect and revert member? Chap13 p37 L4
remind intersectall Chap13 p37 L5
modify intersectall Chap13 p38 L2
modify intersectall Chap13 p39 L1 (left)
modify intersectall Chap13 p39 L1 (right)
modify intersectall Chap13 p41 L1 (left)
modify intersectall Chap13 p41 L1 (right)
modify intersect Chap13 p48 L1
modify intersectall Chap13 p49 L4
modify intersectall Chap13 p50 L2
modify rember Chap13 p52 L7
add rember-beyond-first Chap13 p54 L2
add rember-upto-last Chap13 p57 L1