Never thought of using "by definition, all numbers can be divided by a prime" tu merge the two cases. It's not that shorter, but is IMHO quite elegant, I'll remember it. Thanks for correcting me.
Well, it's not by definition, but "every number is divisible by a prime" is fairly obvious (just keep dividing until you reach a prime) and can technically be proven by using (strong) induction.
Never thought of using "by definition, all numbers can be divided by a prime" tu merge the two cases. It's not that shorter, but is IMHO quite elegant, I'll remember it. Thanks for correcting me.