Let
mmlsi1" class="mathmlsrc">mulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022314X16302049&_mathId=si1.gif&_user=111111111&_pii=S0022314X16302049&_rdoc=1&_issn=0022314X&md5=8f0bc7ea82a970bfd09c55d99f04e746" title="Click to view the MathML source">P,Q∈Fq[X]∖{0}mathContainer hidden">mathCode"><math altimg="si1.gif" overflow="scroll"><mi>Pmi><mo>,mo><mi>Qmi><mo>∈mo><msub><mrow><mi mathvariant="double-struck">Fmi>mrow><mrow><mi>qmi>mrow>msub><mo stretchy="false">[mo><mi>Xmi><mo stretchy="false">]mo><mo>∖mo><mo stretchy="false">{mo><mn>0mn><mo stretchy="false">}mo>math> be two copri
me polyno
mials over the finite field
mmlsi124" class="mathmlsrc">mulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022314X16302049&_mathId=si124.gif&_user=111111111&_pii=S0022314X16302049&_rdoc=1&_issn=0022314X&md5=b9264fbb0cd6ddc57c9e30dc465fe92f" title="Click to view the MathML source">FqmathContainer hidden">mathCode"><math altimg="si124.gif" overflow="scroll"><msub><mrow><mi mathvariant="double-struck">Fmi>mrow><mrow><mi>qmi>mrow>msub>math> with
mmlsi11" class="mathmlsrc">mulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022314X16302049&_mathId=si11.gif&_user=111111111&_pii=S0022314X16302049&_rdoc=1&_issn=0022314X&md5=4d8dafdf022fb32645b67ac6b75697f2" title="Click to view the MathML source">degP>degQmathContainer hidden">mathCode"><math altimg="si11.gif" overflow="scroll"><mi mathvariant="normal">degmi><mo>mo><mi>Pmi><mo>>mo><mi mathvariant="normal">degmi><mo>mo><mi>Qmi>math>. We represent each polyno
mial
m>w m> over
mmlsi124" class="mathmlsrc">mulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022314X16302049&_mathId=si124.gif&_user=111111111&_pii=S0022314X16302049&_rdoc=1&_issn=0022314X&md5=b9264fbb0cd6ddc57c9e30dc465fe92f" title="Click to view the MathML source">FqmathContainer hidden">mathCode"><math altimg="si124.gif" overflow="scroll"><msub><mrow><mi mathvariant="double-struck">Fmi>mrow><mrow><mi>qmi>mrow>msub>math> by
using a rational
m>base m>
mmlsi5" class="mathmlsrc">mulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022314X16302049&_mathId=si5.gif&_user=111111111&_pii=S0022314X16302049&_rdoc=1&_issn=0022314X&md5=e18775548425ff80b18ef905fe9327bb" title="Click to view the MathML source">P/QmathContainer hidden">mathCode"><math altimg="si5.gif" overflow="scroll"><mi>Pmi><mo stretchy="false">/mo><mi>Qmi>math> and
m>digits m>
mmlsi6" class="mathmlsrc">mulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022314X16302049&_mathId=si6.gif&_user=111111111&_pii=S0022314X16302049&_rdoc=1&_issn=0022314X&md5=3c0274cac2d9c567c3d57a4aed0d93ac" title="Click to view the MathML source">si∈Fq[X]mathContainer hidden">mathCode"><math altimg="si6.gif" overflow="scroll"><msub><mrow><mi>smi>mrow><mrow><mi>imi>mrow>msub><mo>∈mo><msub><mrow><mi mathvariant="double-struck">Fmi>mrow><mrow><mi>qmi>mrow>msub><mo stretchy="false">[mo><mi>Xmi><mo stretchy="false">]mo>math> satisfying
mmlsi644" class="mathmlsrc">mulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022314X16302049&_mathId=si644.gif&_user=111111111&_pii=S0022314X16302049&_rdoc=1&_issn=0022314X&md5=f8313c89bc82ca7a6cb85f0c012a3c6e" title="Click to view the MathML source">degsi<degPmathContainer hidden">mathCode"><math altimg="si644.gif" overflow="scroll"><mi mathvariant="normal">degmi><mo>mo><msub><mrow><mi>smi>mrow><mrow><mi>imi>mrow>msub><mo><mo><mi mathvariant="normal">degmi><mo>mo><mi>Pmi>math>.
m>Digit expansions m> of this type are also defined for for
mal Laurent series over
mmlsi124" class="mathmlsrc">mulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022314X16302049&_mathId=si124.gif&_user=111111111&_pii=S0022314X16302049&_rdoc=1&_issn=0022314X&md5=b9264fbb0cd6ddc57c9e30dc465fe92f" title="Click to view the MathML source">FqmathContainer hidden">mathCode"><math altimg="si124.gif" overflow="scroll"><msub><mrow><mi mathvariant="double-struck">Fmi>mrow><mrow><mi>qmi>mrow>msub>math>. We prove uniqueness and auto
matic properties of these expansions. Although the
m>ω m>-language of the possible digit strings is not regular, we are able to characterize the digit expansions of algebraic ele
ments. In particular, we give a version of Christol's Theore
m by showing that the digit string of the digit expansion of a for
mal Laurent series is auto
matic if and only if the series is algebraic over
mmlsi193" class="mathmlsrc">mulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022314X16302049&_mathId=si193.gif&_user=111111111&_pii=S0022314X16302049&_rdoc=1&_issn=0022314X&md5=ab21ee811c9f8af161d6673fc9a73037" title="Click to view the MathML source">Fq[X]mathContainer hidden">mathCode"><math altimg="si193.gif" overflow="scroll"><msub><mrow><mi mathvariant="double-struck">Fmi>mrow><mrow><mi>qmi>mrow>msub><mo stretchy="false">[mo><mi>Xmi><mo stretchy="false">]mo>math>. Finally, we study relations between digit expansions of for
mal Laurent series and a finite fields version of Mahler's 3/2-proble
m.