Opening double angle bracket, like two stacked chevrons pointing left, used in Z notation and mathematical writing.
U+27E9MATHEMATICAL RIGHT ANGLE BRACKETU+27EBMATHEMATICAL RIGHT DOUBLE ANGLE BRACKETU+27E8MATHEMATICAL LEFT ANGLE BRACKETU+27ECMATHEMATICAL LEFT WHITE TORTOISE SHELL BRACKETU+27E7MATHEMATICAL RIGHT WHITE SQUARE BRACKETU+27EDMATHEMATICAL RIGHT WHITE TORTOISE SHELL BRACKETU+27E6MATHEMATICAL LEFT WHITE SQUARE BRACKETU+27EEMATHEMATICAL LEFT FLATTENED PARENTHESISU+27E5WHITE SQUARE WITH RIGHTWARDS TICKU+27EFMATHEMATICAL RIGHT FLATTENED PARENTHESISU+27E4WHITE SQUARE WITH LEFTWARDS TICKU+27E3WHITE CONCAVE-SIDED DIAMOND WITH RIGHTWARDS TICK48 characters in the Miscellaneous Mathematical Symbols-A Unicode block.
U+27C0THREE DIMENSIONAL ANGLEU+27C1WHITE TRIANGLE CONTAINING SMALL WHITE TRIANGLEU+27C2PERPENDICULARU+27C3OPEN SUBSETU+27C4OPEN SUPERSETU+27C5LEFT S-SHAPED BAG DELIMITERU+27C6RIGHT S-SHAPED BAG DELIMITERU+27C7OR WITH DOT INSIDEU+27C8REVERSE SOLIDUS PRECEDING SUBSETU+27C9SUPERSET PRECEDING SOLIDUSU+27CAVERTICAL BAR WITH HORIZONTAL STROKEU+27CBMATHEMATICAL RISING DIAGONALU+27CCLONG DIVISIONU+27CDMATHEMATICAL FALLING DIAGONALU+27CESQUARED LOGICAL ANDU+27CFSQUARED LOGICAL ORU+27D0WHITE DIAMOND WITH CENTRED DOTU+27D1AND WITH DOTU+27D2ELEMENT OF OPENING UPWARDSU+27D3LOWER RIGHT CORNER WITH DOTU+27D4UPPER LEFT CORNER WITH DOTU+27D5LEFT OUTER JOINU+27D6RIGHT OUTER JOINU+27D7FULL OUTER JOINU+27D8LARGE UP TACKU+27D9LARGE DOWN TACKU+27DALEFT AND RIGHT DOUBLE TURNSTILEU+27DBLEFT AND RIGHT TACKU+27DCLEFT MULTIMAPU+27DDLONG RIGHT TACKU+27DELONG LEFT TACKU+27DFUP TACK WITH CIRCLE ABOVEU+27E0LOZENGE DIVIDED BY HORIZONTAL RULEU+27E1WHITE CONCAVE-SIDED DIAMONDU+27E2WHITE CONCAVE-SIDED DIAMOND WITH LEFTWARDS TICKU+27E3WHITE CONCAVE-SIDED DIAMOND WITH RIGHTWARDS TICKU+27E4WHITE SQUARE WITH LEFTWARDS TICKU+27E5WHITE SQUARE WITH RIGHTWARDS TICKU+27E6MATHEMATICAL LEFT WHITE SQUARE BRACKETU+27E7MATHEMATICAL RIGHT WHITE SQUARE BRACKETU+27E8MATHEMATICAL LEFT ANGLE BRACKETU+27E9MATHEMATICAL RIGHT ANGLE BRACKETU+27EAMATHEMATICAL LEFT DOUBLE ANGLE BRACKETU+27EBMATHEMATICAL RIGHT DOUBLE ANGLE BRACKETU+27ECMATHEMATICAL LEFT WHITE TORTOISE SHELL BRACKETU+27EDMATHEMATICAL RIGHT WHITE TORTOISE SHELL BRACKETU+27EEMATHEMATICAL LEFT FLATTENED PARENTHESISU+27EFMATHEMATICAL RIGHT FLATTENED PARENTHESIS