#Is this proof correct? (Order is reflexive)

9 messages · Page 1 of 1 (latest)

proven vector
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I'm trying to prove a≥a from Analysis I. Is this proof correct / how could it be written better?

Proof.
Let a∈N. We will show a≥a using induction. In the base case, a=0. By def 2.2.1, a = 0 + a. By the commutative property, a = a + 0. By def 2.2.11, a≥a. This proves the base case.

We will now prove the inductive case by showing a++≥a++. By the same logic as the base case, (a++) = 0 + (a++) = (a++) + 0. Because (a++) = (a++) + 0, By def 2.2.11, a++≥a++. This proves the inductive case.

pulsar bear
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it is correct but you don't need induction to prove this

proven vector
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Thanks 🙂

royal cape
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a ∈ N, a ≥ a:
    have a = a ∨ a > a from a ≥ a,
    have a = a from left a = a ∨ a > a,
    show a = a from identity.
QED
proven vector
pulsar bear
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usually ">=" is defined at "equal or >", or like, ">" is defined as ">= but unequal", so that proof would be the usual

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but in this case the definition is specific, you need to follow the process of writting that sum for some natural number etc

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btw this is from Terence Tao's book, isn't it?