[Introduction] Fix Contribution

[a2975667]

a quick note on contributions; contributions have a specific argumentative format; a contribution can be an algorithm, a framework, a methodology, a highly significant empirical finding

but..

each paper contribution has four parts to the argument:

1. state the contribution; e.g. we developed a linear time algorithm
2. contrast with prior work; e.g. In contrast, the state of the art is by smith et. al. who developed algorithm Y that had quadratic time complexity.
3. the key insight for our algorithm was...
4. our algorithm (or method, or finding) is significant because... papers typically have 2-3 contributions; of course you can have more, but arguing for four significant contributions is hard. _{View in Slack}