What ⊫ means
Read the formal system’s definition; the glyph has no fixed reading. In a logic text, ⊫ can mark a relation chosen by the author; its extra bars alone do not tell you which one. Look for the notation’s definition before reading it as proof, truth, forcing, or another relation.
Is ⊫ the same as or ?
No; they are separate symbols with different conventions. commonly marks derivability from assumptions by formal rules; commonly marks semantic consequence or that a model satisfies a formula. Those conventions help distinguish the related signs but do not settle ⊫.
The single turnstile has an older history. Frege’s 1879 Begriffsschrift, a book introducing logical notation, placed a vertical judgement stroke before a horizontal content line to mark a statement as asserted. Modern is a related sign often used for derivability; that lineage does not assign a reading to ⊫.
Don't confuse it with
2
Related characters
1
Questions 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.
More like this
10
How to type or find ⊫
- Search it as
- double turnstile symbol · double vertical bar turnstile · VDash · VDash LaTeX · turnstile notation · ⊫ vs ⊨
- Shows up in
- Anything that takes text · its shape is whatever your font draws
⊫\22AB\VDash.Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.