  Jet cross sections have been measured for the first time in proton-proton
collisions at a centre-of-mass energy of 7 TeV using the ATLAS detector. The
measurement uses an integrated luminosity of 17 nb-1 recorded at the Large
Hadron Collider. The anti-kt algorithm is used to identify jets, with two jet
resolution parameters, R = 0.4 and 0.6. The dominant uncertainty comes from the
jet energy scale, which is determined to within 7% for central jets above 60
GeV transverse momentum. Inclusive single-jet differential cross sections are
presented as functions of jet transverse momentum and rapidity. Dijet cross
sections are presented as functions of dijet mass and the angular variable
$\chi$. The results are compared to expectations based on next-to-leading-order
QCD, which agree with the data, providing a validation of the theory in a new
kinematic regime.
