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Based on a general formulation for discrete-time quantum mechanics, introduced
by M. Khorrami ({\it Annals
Phys}. {\bf 224} (1995), 101), symmetries in discrete-time
quantum mechanics are investigated. It is shown that any classical continuous
symmetry leads to a conserved quantity in classical mechanics, as well as
quantum mechanics. The transformed wave function, however, has the correct
evolution if and only if the symmetry is nonanomalous.
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