I am wondering if the nonzero rationals with operation $x\circ y = xy/7$ a group. I think it may be and I found the identity to be 7 and found inverses for each element. Mark
groups and checking group properties
3
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abstract-algebra
group-theory
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5You probably mean to ask "is $(\mathbb R\setminus\{0\},\circ)$ a group, where $a\circ b = ab/7$"? – 2011-03-17
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4A group is a set together with an operation. You provided an expression, which is not a group. What is the set, and what is the operation on the set? – 2011-03-17
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0Yes sorry I meant to specify that 0 is not in the set and that the operation is in Q* . I hope this makes the question a little clearer Thnx Mark – 2011-03-20