diff options
| author | Franklin Wei <git@fwei.tk> | 2017-04-29 18:21:56 -0400 |
|---|---|---|
| committer | Franklin Wei <git@fwei.tk> | 2017-04-29 18:24:42 -0400 |
| commit | 881746789a489fad85aae8317555f73dbe261556 (patch) | |
| tree | cec2946362c4698c8db3c10f3242ef546c2c22dd /apps/plugins/puzzles/src/html/group.html | |
| parent | 03dd4b92be7dcd5c8ab06da3810887060e06abd5 (diff) | |
| download | rockbox-881746789a489fad85aae8317555f73dbe261556.zip rockbox-881746789a489fad85aae8317555f73dbe261556.tar.gz rockbox-881746789a489fad85aae8317555f73dbe261556.tar.bz2 rockbox-881746789a489fad85aae8317555f73dbe261556.tar.xz | |
puzzles: refactor and resync with upstream
This brings puzzles up-to-date with upstream revision
2d333750272c3967cfd5cd3677572cddeaad5932, though certain changes made
by me, including cursor-only Untangle and some compilation fixes
remain. Upstream code has been moved to its separate subdirectory and
future syncs can be done by simply copying over the new sources.
Change-Id: Ia6506ca5f78c3627165ea6791d38db414ace0804
Diffstat (limited to 'apps/plugins/puzzles/src/html/group.html')
| -rw-r--r-- | apps/plugins/puzzles/src/html/group.html | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/apps/plugins/puzzles/src/html/group.html b/apps/plugins/puzzles/src/html/group.html new file mode 100644 index 0000000..c0f52de --- /dev/null +++ b/apps/plugins/puzzles/src/html/group.html @@ -0,0 +1,52 @@ +unfinished:Group +<p> +Fill in the grid with the letters shown to the top and left of it, so +that the full grid is a valid +<a href="http://en.wikipedia.org/wiki/Cayley_table">Cayley table</a> +for a +<a href="http://en.wikipedia.org/wiki/Group_(mathematics)">group</a>. +<p> +If you don't already know what a group is, I don't really recommend +trying to play this game. But if you want to try anyway, the above is +equivalent to saying that the following conditions must be satisfied: +<ul> +<li> +<strong>Latin square</strong>. Every row and column must contain +exactly one of each letter. +<li> +<strong>Identity</strong>. There must be some letter <i>e</i> such +that, for all <i>a</i>, the letter in row <i>e</i> column <i>a</i> and +the one in row <i>a</i> column <i>e</i> are both <i>a</i>. In the +default mode, this letter is always <i>e</i> and its row and column +are filled in for you; by reconfiguring the game using the Type menu, +you can select a mode in which you have to work out which letter is +the identity. +<li> +<strong>Inverses</strong>. For every letter <i>a</i>, there must be +some letter <i>b</i> (which may sometimes be the same letter +as <i>a</i>) such that the letters in row <i>a</i> column <i>b</i> and +in row <i>b</i> column <i>a</i> are both the identity letter (as +defined above). +<li> +<strong>Associativity</strong>. For every combination of +letters <i>a</i>, <i>b</i>, and <i>c</i>, denote the letter in +row <i>a</i> column <i>b</i> by <i>d</i>, and the one in row <i>b</i> +column <i>c</i> by <i>e</i>. Then the letters in row <i>d</i> +column <i>c</i> and in row <i>a</i> column <i>e</i> must be the same. +</ul> +<p> +To place a letter, click in a square to select it, then type the +letter on the keyboard. To erase a letter, click to select a square +and then press Backspace. +<p> +Right-click in a square and then type a letter to add or remove the +number as a pencil mark, indicating letters that you think +<em>might</em> go in that square. +<p> +You can rearrange the order of elements in the rows and columns by +dragging the column or row headings back and forth. (The rows and +columns will stay in sync with each other.) Also, +left-clicking <em>between</em> two row or column headings will add or +remove a thick line between those two rows and the corresponding pair +of columns (which is useful if you're considering a subgroup and its +cosets). |