What ⊮ means
It denies forcing; ⊬ denies a proof.
A Kripke model—a framework for checking formulas at possible states or worlds—sets conditions for when each proposition is forced. ⊮ says those conditions do not make this proposition hold at this state.
That is a claim about meaning within a model; by itself, it does not say whether the proposition can be proved from assumptions.
Don't confuse it with
1Questions people ask
1Why does ⊮ show as a box on some devices?
Because that device's fonts have no glyph for it. The character is still correct and still copies correctly — the box is a missing glyph, not a broken character.
How to type ⊮
Windows (Word)
Alt+XType 22AE, then Alt+X to get ⊮.
Windows
Win+Rrun charmap for the full table, or use the emoji picker's Ω symbols tab (Win + .).
macOS
Control+Command+SpaceOpen the character viewer and search “does not force”.
Linux
Ctrl+Shift+UType 22ae, then Enter or Space.
HTML
⊮CSS
\22AELaTeX
In math mode, enter `\nVdash`; your LaTeX symbol setup must define the command and include the glyph.
Codes and encoding1 code points
HTML decimal
⊮
HTML hex
⊮
CSS content
content: "\22AE";
Each escape is closed by the next backslash; a trailing space is needed before a literal hex digit.
URL encoded
%E2%8A%AE
1
On screen
1
Code points
1
JS .length
3
UTF-8 bytes
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.