... also meant to mention that "Induct_on" and "completeInduct_on" have
online documentation.


On Sat, Jan 5, 2019 at 3:20 PM Konrad Slind <konrad.sl...@gmail.com> wrote:

> There is discussion of something like this in the Euclid's Theorem
> tutorial. You can do Induct_on `j - i` or do the trick where you prove ?k.
> j = i + SUC k, eliminate j, and then induct on k.
>
> Konrad.
>
>
> On Sat, Jan 5, 2019 at 12:35 PM Chun Tian (binghe) <binghe.l...@gmail.com>
> wrote:
>
>> sorry, "i ≤ j” should be “i < j” actually:
>>
>>    ∀i j. i < j ⇒ f (SUC i) ⊆ f j
>>    ------------------------------------
>>      0.  ∀n. f n ⊆ f (SUC n)
>>      1.  ∀n. 0 < n ⇒ f 0 ⊆ f n
>>
>> > Il giorno 05 gen 2019, alle ore 19:32, Chun Tian (binghe) <
>> binghe.l...@gmail.com> ha scritto:
>> >
>> > Hi,
>> >
>> > I have the following goal to prove: (f : num -> ‘a set)
>> >
>> >   ∀i j. i ≤ j ⇒ f (SUC i) ⊆ f j
>> >   ------------------------------------
>> >     0.  ∀n. f n ⊆ f (SUC n)
>> >
>> > but how can I do the induction on … e.g. `j - i`?
>> >
>> > —Chun
>> >
>>
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