Peter Taylor
Reputation
5,400
Top tag
Next privilege 10,000 Rep.
Access moderator tools
 Apr 17 comment Maximum number of edges in a (n,n) bipartite graph, that doens't have a complete bipartite subgraph $K_{r,r}$ There's a trivial solution: let $c=0$. If $r=1$ then that's tight. Apr 17 comment Prove that there are two frogs in one square. Harry Dunlop's answer already provides a solution: this is essentially just Hilbert's Hotel backwards. Apr 16 revised an intriguing integral $I=\int\limits_{0}^{4} \frac{dx}{4+2^x}$ edited tags Apr 16 revised Inverse quantile function for $\sin^2(x)$ edited tags Apr 15 comment Game Theory - Voting The procedure as described doesn't seem to always select a winner. If A gets 51%, B gets 49%, C gets 0%, and D gets 0% then the first round of eliminations should ditch C and D, but neither A or B can be eliminated. Apr 15 comment Proof that $12$ in a row tic-tac-toe is a tie game? Tic-tae-toe on an infinite grid can never end in a tie. Presumably you mean that neither player has a winning strategy. Apr 8 answered Round Robin for Team Matches Apr 8 comment Round Robin for Team Matches Does en.wikipedia.org/wiki/… help? Apr 8 comment Making 7 vertices triangle free graph bipartite by deleting an edge There's a trivial counter-example: the graph with $|V|=7$ and $|E|=0$. Apr 7 comment Characterizing a certain set of matrices arising from binary trees Your diagram doesn't look like a binary tree. It could be converted into a binary tree by inserting three non-leaf nodes, but if this is done symmetrically then the distances between leaf nodes would be $2$ and $4$. What is the actual tree structure? Apr 4 comment Josephus Variant You might want to check your results against oeis.org/A032434. Apr 4 revised Physics Related Watt Question edited tags Apr 2 comment Minimal DFA for a given regular expression Are you familiar with the Myhill-Nerode theorem? Apr 1 reviewed Edit Order and element set of the group with presentation $\langle a,b \;|\; a^9=1, b^3=a^3, [a,b]=a^3\rangle$ Apr 1 revised Order and element set of the group with presentation $\langle a,b \;|\; a^9=1, b^3=a^3, [a,b]=a^3\rangle$ deleted 2 characters in body Mar 29 comment Are there useful combinatorial constructions of grammars? I don't have enough to make an answer, and you stand more chance of getting a more complete answer if I stick to comments. But Flajolet and Sedgewick's book on Analytic Combinatorics seems to address something related to context-free grammars, so you might want to try to find a copy. Mar 28 comment Are there useful combinatorial constructions of grammars? I think you need to be a bit more careful in distinguishing between a rule from a CFG and the CFG itself. I can understand that you might want to identify the CFG with the rule which defines its initial non-terminal, but things might become clearer if you define the size of a rule as the number of symbols in its definition and the size of a grammar as the sum of the sizes of the rules reachable from its initial non-terminal. For a start, that immediately highlights the importance of the transitive closure, and suggests looking at graph combinatorics. Mar 22 comment Maximum board position in 2048 game How is the score computed from the move sequence? Mar 16 answered Distinguishing between hash function digest and message corruption Mar 10 answered What is the pupose of using minute and seconds with degree?