Goldbach's conjecture states that every even integer which is greater than 2 can be expressed as the sum of two prime numbers.
This has been shown to be correct for integers up to approx 4 quintillion but has not been proven.
The Poincaré Conjecture.
A counter-example.
Counter Example
A counter example is a statement that shows conjecture is false.
A counterexample.
A famous conjecture is the Twin prime conjecture, which states that there are infinitely many "twin primes" - primes which are 2 apart (for example, 11 and 13, or 17 and 19, are twin primes)
Counter-example
conuturexample
pie tree
Give a counter-example.
hypothesis
There is no logical conjecture that can be made for what could be an irregular polygon with an unknown number of sides. Of course, you could always conjecture anything. For example, that they will taste of strawberries. A conjecture that, I guess, will be disproved quite easily.