Hot questions in Discrete Mathematics

30 votes
6 answers
125
Indicate which of the following well-formed formulae are valid:$\left(P\Rightarrow Q\right) {\wedge} \left(Q \Rightarrow R\right) \Rightarrow \left(P \Rightarrow R\right)...
51 votes
5 answers
127
38 votes
9 answers
129
How many $4$-digit even numbers have all $4$ digits distinct?$2240$$2296$$2620$$4536$
46 votes
6 answers
134
The minimum number of colours required to colour the vertices of a cycle with $n$ nodes in such a way that no two adjacent nodes have the same colour is$2$$3$$4$$n-2 \lef...
1 votes
3 answers
137
The chromatic number of a graph is the minimum number of colours used in a proper colouring of the graph. The chromatic number of the following graph is __________.