--- /dev/null
+
+<!--
+ File mmlextra.ent produced by the XSL script mmldtd.xsl
+ from input data in unicode.xml.
+
+ Please report any errors to
+ David Carlisle <davidc@nag.co.uk>.
+
+ The numeric character values assigned to each entity
+ (should) match either official Unicode assignments
+ or assignments provisionally allocated by the
+ Unicode Consortium based on the characters in the `STIX'
+ propsal for mathematics. Note that these assignments
+ have not been ratified by the corresponding ISO
+ committee and thus should be considered liable to
+ change.
+
+-->
+
+<!ENTITY af "⁡" ><!--short form of ⁡ -->
+<!ENTITY ApplyFunction "⁡" ><!--character showing function application in presentation tagging -->
+<!ENTITY Assign "≔" ><!--assignment operator -->
+<!ENTITY CapitalDifferentialD "ⅅ" ><!--D for use in differentials, e.g., within integrals -->
+<!ENTITY Cayleys "ℭ" ><!--the non-associative ring of octonions or Cayley numbers -->
+<!ENTITY complexes "ℂ" ><!--the field of complex numbers -->
+<!ENTITY Cross "⨯" ><!--cross or vector product -->
+<!ENTITY dd "ⅆ" ><!--short form of ⅆ -->
+<!ENTITY DD "ⅅ" ><!--short form of CapitalDifferentialD -->
+<!ENTITY DifferentialD "ⅆ" ><!--d for use in differentials, e.g., within integrals -->
+<!ENTITY DownArrowBar "⤓" ><!--down arrow to bar -->
+<!ENTITY DownBreve "̑" ><!--breve, inverted (non-spacing) -->
+<!ENTITY DownLeftRightVector "⥐" ><!--left-down-right-down harpoon -->
+<!ENTITY DownLeftTeeVector "⥞" ><!--left-down harpoon from bar -->
+<!ENTITY DownLeftVectorBar "⥖" ><!--left-down harpoon to bar -->
+<!ENTITY DownRightTeeVector "⥟" ><!--right-down harpoon from bar -->
+<!ENTITY DownRightVectorBar "⥗" ><!--right-down harpoon to bar -->
+<!ENTITY DownTeeArrow "↧" ><!--alias for mapstodown -->
+<!ENTITY ee "ⅇ" ><!--short form of ⅇ -->
+<!ENTITY EmptySmallSquare "◽" ><!--empty small square -->
+<!ENTITY EmptyVerySmallSquare "◽" ><!--empty small square -->
+<!ENTITY Equal "⩵" ><!--two consecutive equal signs -->
+<!ENTITY expectation "ℰ" ><!--expectation (operator) -->
+<!ENTITY exponentiale "ℯ" ><!--base of the Napierian logarithms -->
+<!ENTITY ExponentialE "ⅇ" ><!--e use for the exponential base of the natural logarithms -->
+<!ENTITY FilledSmallSquare "◾" ><!--filled small square -->
+<!ENTITY FilledVerySmallSquare "◾" ><!--filled very small square -->
+<!ENTITY Fouriertrf "ℱ" ><!--Fourier transform -->
+<!ENTITY GreaterGreater "⪢" ><!--alias for GT -->
+<!ENTITY HilbertSpace "ℋ" ><!--Hilbert space -->
+<!ENTITY HorizontalLine "─" ><!--short horizontal line -->
+<!ENTITY ic "​" ><!--short form of ⁣ -->
+<!ENTITY ii "ⅈ" ><!--short form of ⅈ -->
+<!ENTITY ImaginaryI "ⅈ" ><!--i for use as a square root of -1 -->
+<!ENTITY imagline "ℐ" ><!--the geometric imaginary line -->
+<!ENTITY integers "ℤ" ><!--the ring of integers -->
+<!ENTITY InvisibleComma "​" ><!--used as a separator, e.g., in indices -->
+<!ENTITY InvisibleTimes "⁢" ><!--marks multiplication when it is understood without a mark -->
+<!ENTITY it "⁢" ><!--short form of ⁢ -->
+<!ENTITY Laplacetrf "ℒ" ><!--Laplace transform -->
+<!ENTITY larrb "⇤" ><!--leftwards arrow to bar -->
+<!ENTITY LeftArrowBar "⇤" ><!--alias for larrb -->
+<!ENTITY LeftDownTeeVector "⥡" ><!--down-left harpoon from bar -->
+<!ENTITY LeftDownVectorBar "⥙" ><!--down-left harpoon to bar -->
+<!ENTITY LeftRightVector "⥎" ><!--left-up-right-up harpoon -->
+<!ENTITY LeftTeeArrow "↤" ><!--alias for mapstoleft -->
+<!ENTITY LeftTeeVector "⥚" ><!--left-up harpoon from bar -->
+<!ENTITY LeftTriangleBar "⧏" ><!--not left triangle, vertical bar -->
+<!ENTITY LeftUpDownVector "⥑" ><!--up-left-down-left harpoon -->
+<!ENTITY LeftUpTeeVector "⥠" ><!--up-left harpoon from bar -->
+<!ENTITY LeftUpVectorBar "⥘" ><!--up-left harpoon to bar -->
+<!ENTITY LeftVectorBar "⥒" ><!--left-up harpoon to bar -->
+<!ENTITY LessLess "⪡" ><!--alias for Lt -->
+<!ENTITY mapstodown "↧" ><!--downwards arrow from bar -->
+<!ENTITY mapstoleft "↤" ><!--leftwards arrow from bar -->
+<!ENTITY mapstoup "↥" ><!--upwards arrow from bar -->
+<!ENTITY Mellintrf "ℳ" ><!--Mellin transform -->
+<!ENTITY naturals "ℕ" ><!--the semi-ring of natural numbers -->
+<!ENTITY nbump "≎̸" ><!--not bumpy equals -->
+<!ENTITY nbumpe "≏̸" ><!--not bumpy single equals -->
+<!ENTITY NegativeMediumSpace " ⁣" ><!--space of width -4/18 em -->
+<!ENTITY NegativeThickSpace " ⁣" ><!--space of width -5/18 em -->
+<!ENTITY NegativeThinSpace " ⁣" ><!--space of width -3/18 em -->
+<!ENTITY NegativeVeryThinSpace " ⁣" ><!--space of width -1/18 em -->
+<!ENTITY nesim "≂̸" ><!--not equal or similar -->
+<!ENTITY NewLine "
" ><!--force a line break; line feed -->
+<!ENTITY NoBreak "" ><!--never break line here -->
+<!ENTITY NotCupCap "≭" ><!--alias for &nasymp; -->
+<!ENTITY NotEqualTilde "≂̸" ><!--alias for ≂̸ -->
+<!ENTITY NotHumpDownHump "≎̸" ><!--alias for ≎̸ -->
+<!ENTITY NotHumpEqual "≏̸" ><!--alias for ≏̸ -->
+<!ENTITY NotLeftTriangleBar "⧏̸" ><!--not left triangle, vertical bar -->
+<!ENTITY NotNestedGreaterGreater "⒢̸" ><!--not double greater-than sign -->
+<!ENTITY NotNestedLessLess "⒡̸" ><!--not double less-than sign -->
+<!ENTITY NotRightTriangleBar "⧐̸" ><!--not vertical bar, right triangle -->
+<!ENTITY NotSquareSubset "⊏̸" ><!--square not subset -->
+<!ENTITY NotSquareSuperset "⊐̸" ><!--negated set-like partial order operator -->
+<!ENTITY NotSucceedsTilde "≿̸" ><!--not succeeds or similar -->
+<!ENTITY OverBar "¯" ><!--over bar -->
+<!ENTITY OverBrace "︷" ><!--over brace -->
+<!ENTITY OverBracket "⎴" ><!--over bracket -->
+<!ENTITY OverParenthesis "︵" ><!--over parenthesis -->
+<!ENTITY planckh "ℎ" ><!--the ring (skew field) of quaternions -->
+<!ENTITY Poincareplane "ℌ" ><!--the Poincare upper half-plane -->
+<!ENTITY primes "ℙ" ><!--the prime natural numbers -->
+<!ENTITY Product "∏" ><!--alias for &prod -->
+<!ENTITY quaternions "ℍ" ><!--the ring (skew field) of quaternions -->
+<!ENTITY rarrb "⇥" ><!--leftwards arrow to bar -->
+<!ENTITY rationals "ℚ" ><!--the field of rational numbers -->
+<!ENTITY realine "ℛ" ><!--the geometric real line -->
+<!ENTITY reals "ℝ" ><!--the field of real numbers -->
+<!ENTITY RightArrowBar "⇥" ><!--alias for rarrb -->
+<!ENTITY RightDownTeeVector "⥝" ><!--down-right harpoon from bar -->
+<!ENTITY RightDownVectorBar "⥕" ><!--down-right harpoon to bar -->
+<!ENTITY RightTeeVector "⥛" ><!--right-up harpoon from bar -->
+<!ENTITY RightTriangleBar "⧐" ><!--vertical bar, right triangle -->
+<!ENTITY RightUpDownVector "⥏" ><!--up-right-down-right harpoon -->
+<!ENTITY RightUpTeeVector "⥜" ><!--up-right harpoon from bar -->
+<!ENTITY RightUpVectorBar "⥔" ><!--up-right harpoon to bar -->
+<!ENTITY RightVectorBar "⥓" ><!--up-right harpoon to bar -->
+<!ENTITY RoundImplies "⥰" ><!--round implies -->
+<!ENTITY RuleDelayed "⧴" ><!--rule-delayed (colon right arrow) -->
+<!ENTITY ShortDownArrow "⌄⁣" ><!--short down arrow -->
+<!ENTITY ShortUpArrow "⌃⁣" ><!--short up arrow -->
+<!ENTITY Tab "	" ><!--tabulator stop; horizontal tabulation -->
+<!ENTITY ThickSpace " " ><!--space of width 5/18 em -->
+<!ENTITY UnderBar "̲" ><!--combining low line -->
+<!ENTITY UnderBrace "︸" ><!--under brace -->
+<!ENTITY UnderBracket "⎵" ><!--under bracket -->
+<!ENTITY UpArrowBar "⤒" ><!--up arrow to bar -->
+<!ENTITY UpTeeArrow "↥" ><!--Alias mapstoup -->
+<!ENTITY VerticalLine "❘" ><!--short vertical line -->
+<!ENTITY VerticalSeparator "❘" ><!--vertical separating operator -->
+<!ENTITY zeetrf "ℨ" ><!--zee transform -->
+<!ENTITY ZeroWidthSpace "​" ><!--zero width space -->