Fdtxjr

I would like to have a command that shrinks down the size of $varhexagon$ from the wasysym package in latex to a very small size.

In principle, $tiny varhexagon$ does what I want, but apparently the command "tiny" is not allowed in math mode.

Is there a way to circumvent this?-Note that scriptscriptstyle does not seem to give the same size as tiny.

In short, I want a command that does the same as $A_tiny varhexagon$ but does not use the illegal command tiny.

Indeed, tiny is a text mode command and thus is not allowed in math mode.

What you may be looking for is

newcommandtinyvarhexagonvcenterhboxscalebox0.5$varhexagon$

where scalebox is a macro provided by the graphic package and vcenter and hbox are TeX "primitive". tiny corresponds to a linear reduction in font size of 50%; hence the 0.5 scaling factor. With this definition, the tiny hexagon is centered vertically on the math axis. If you would rather have the resized symbol placed on the baseline, just omit the vcenterhbox... "wrapper".

documentclassarticle
usepackagewasysym % for "varhexagon" macro
usepackagegraphicx% for "scalebox" macro
newcommandtinyvarhexagonvcenterhboxscalebox0.5$varhexagon$
 % ("vcenter" and "hbox" are TeX primitives)

begindocument
$avarhexagon a$ $atinyvarhexagon a$ $ascalebox0.5$varhexagon$ a$ 

$A_varhexagon$ $A_tinyvarhexagon$ $A_scalebox0.5$varhexagon$$
enddocument 

You can load the font with a different scaling factor:

documentclassarticle

usepackagewasysym % just for comparison

DeclareFontFamilyUwasysmall
DeclareFontShapeUwasysmallmn
 <-5.5> s*[0.75] wasy5
 <5.5-6.5> s*[0.75] wasy6
 <6.5-7.5> s*[0.75] wasy7
 <7.5-8.5> s*[0.75] wasy8
 <8.5-9.5> s*[0.75] wasy9
 <9.5-> s*[0.75] wasy10

DeclareFontShapeUwasysmallbn
 <-5.5> s*[0.75] wasyb5
 <5.5-6.5> s*[0.75] wasyb6
 <6.5-7.5> s*[0.75] wasyb7
 <7.5-8.5> s*[0.75] wasyb8
 <8.5-9.5> s*[0.75] wasyb9
 <9.5-> s*[0.75] wasyb10

DeclareFontShapeUwasysmallbxn <-> sub * wasysmall/b/n

DeclareSymbolFontwasysmallUwasysmallmn
SetSymbolFontwasysmallboldUwasysmallbn

DeclareMathSymbolsmallhexagonmathordwasysmall57

begindocument

tinyvarhexagon $scriptstylesmallhexagon$ $A_smallhexagon$

enddocument

Note that loading wasysym is not required, I did just for the comparison.

You can avoid wasting a symbol font:

documentclassarticle
usepackageamsmath

DeclareFontFamilyUwasysmall
DeclareFontShapeUwasysmallmn
 <-5.5> s*[0.75] wasy5
 <5.5-6.5> s*[0.75] wasy6
 <6.5-7.5> s*[0.75] wasy7
 <7.5-8.5> s*[0.75] wasy8
 <8.5-9.5> s*[0.75] wasy9
 <9.5-> s*[0.75] wasy10


newcommandsmallhexagontextusefontUwasysmallmnsymbol57

begindocument

$A_smallhexagon$

enddocument

If you just need the symbol to change size in subscripts, you can do in a different way:

documentclassarticle
usepackageamsmath
usepackagewasysym

DeclareMathSymbolmhexagonmathordwasy57

begindocument

$A_varhexagon$ (wrong)

$A_mhexagon$

enddocument

As you can see, this approach works for both smaller text sizes as well as smaller math sizes.

documentclassarticle
usepackagewasysym,scalerel,lmodern
newcommandxvarhexagonscaletovarhexagon1.4LMex
begindocument
$varhexagon xxvarhexagon
scriptstyle xxvarhexagon
scriptscriptstyle xxvarhexagon$

small$varhexagon xxvarhexagon
scriptstyle xxvarhexagon
scriptscriptstyle xxvarhexagon$

footnotesize$varhexagon xxvarhexagon
scriptstyle xxvarhexagon
scriptscriptstyle xxvarhexagon$

scriptsize$varhexagon xxvarhexagon
scriptstyle xxvarhexagon
scriptscriptstyle xxvarhexagon$

tiny$varhexagon xxvarhexagon
scriptstyle xxvarhexagon
scriptscriptstyle xxvarhexagon$

normalsize$x_xvarhexagon =3xvarhexagon y$
enddocument

The amsmath package also provides the text command which allows text mode commands inside math mode without warnings (see also the answer by @egreg above).

MWE:

documentclassarticle
usepackageamsmath
usepackagewasysym

begindocument
Atinyvarhexagon

$A_texttinyvarhexagon$
enddocument

Result: