Less Than Minimum Property
if a < minimum value of stack xs, then minimum value of stack [ a, xs ] = a
If we know that some value a is less than the minimum value of some list, then the minimum value of the list that includes a is simply a.
Examples
if 5 < minimum value of stack [ 7, [ ] ], then minimum value of stack [ 5, [ 7, [ ] ] ] = 5
if 1 < minimum value of stack [ 2, [ 3, [ 4, [ ] ] ] ], then minimum value of stack [ 1, [ 2, [ 3, [ 4, [ ] ] ] ] ] = 1
if 1248 < minimum value of stack [ 2000, [ 3300, [ 1450, [ ] ] ] ], then minimum value of stack [ 1248, [ 2000, [ 3300, [ 1450, [ ] ] ] ] ] = 1248
If we know the minimum value of some list, this property can tell us the minimum value of a new larger list. This allows us to prove claims about minimum values.
For instance, in the first example, we know that the minimum of the list [7, []] is simply 7. Then, since 5 is less than 7, we claim that the minimum of [5, [7,[]]] is 5.
If 20 is less than the minimum value of list nums, then what is the minimum value of list [20, nums] ?
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