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Simplify drops a condition the answer's own domain condition states, read in the codomain - #1402
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…he condition beside it #1394's reading: a provided says where the expression has a value, and 1/x at zero has one, the point at infinity, so 1/x provided not x = 0 is a different expression from 1/x and keeps its condition. #1396 dropped it, reading a quotient by d, a negative power of d and a logarithm of d as undefined at the zeros of d; those arms go, and only 0^0 and 0/0 -- d^f or n/d with both vanishing at the zeros of the condition's expression -- are read, a sine, tangent, arcsine or arctangent of something vanishing counting as vanishing. x^x's derivative stays bare, ln(x)/x's derivative keeps its condition as before #1396, and (x + sin(x))/x still has limit 1 at infinity since sin(x)/x is 0/0 at zero. The reading is recorded in the Providedf section of SimplificationContract.md, with the codomain caveat, in the comparison page's provided paragraph, and in the #1396 entry of BREAKING-CHANGES, rewritten to the net behaviour with the day the wider rule stood on master noted. Four suites green; the performance gate passed. Part of #1394. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_012sonx8iAspMiwRwokT1Ura
…read in the codomain #1396 decided by the shape of the node -- a quotient by d, a negative power of d, a logarithm of d, d^f with f vanishing -- what the library already says per node: DomainConditionIn(codomain) is what an expression accepts under the reading it is asked in, a nonzero divisor, a nonzero base or a positive exponent, a nonzero antilogarithm over the complex plane and a positive one over the reals, a cosine that is not zero for a tangent. A provided not e = 0 is redundant where that domain condition already excludes the zeros of e: a conjunct not d = 0 or d > 0 with d vanishing there -- e itself, a positive power of it, a product holding it, a sine, tangent, arcsine or arctangent of such a thing, or a polynomial in the variable e is with no constant term -- or a disjunction every side of which does, as x^x's not x = 0 or x > 0. Nothing in the rule decides what a node accepts, so it follows the codomain: when #217 gives 1/0 a value under the codomains that admit a complex infinity, the quotient's domain condition changes there and the condition beside 1/x stops being redundant by itself. The answers are #1396's, and the shapes the list missed: tan(x) provided not cos(x) = 0 and sin(x)/x provided not x = 0 drop their conditions too. Recorded in the Providedf section of SimplificationContract.md, in the comparison page's provided paragraph and in the #1396 entry of BREAKING-CHANGES. Four suites green; the performance gate passed. Part of #1394. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_012sonx8iAspMiwRwokT1Ura
Rafael-SOWNet
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Reworked (second commit, 56df0be → this) on the thread's conclusion: the rule now asks the answer's own |
This was referenced Sep 17, 2026
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#1394, second half, on the maintainer's reading: a
providedis validated against what the expression accepts under the codomain, and the library already says that per node —DomainConditionIn(codomain). #1396 had hard-coded the shapes (a quotient byd, a negative power ofd, a logarithm ofd,d^fwithfvanishing); this replaces the list with the answer's own domain condition.Change.
IsUndefinedAtTheZerosOf(answer, e)is now: doesanswer.DomainConditionIn(MathS.Settings.Codomain)already exclude the zeros ofe— a conjunctnot d = 0ord > 0withdvanishing at them (eitself, a positive power of it, a product holding it, a sine, tangent, arcsine or arctangent of such a thing, or a polynomial in the variableeis with no constant term), or a disjunction every side of which does (x^x'snot x = 0 or x > 0). Nothing in the rule decides what a node accepts; that stays with the node, so the rule follows the codomain: when #217 gives1/0a value under the codomains that admit a complex infinity, a quotient's domain condition changes there and1/x provided not x = 0stops being redundant by itself. (Two earlier versions of this branch hard-coded "a pole is a value" and then evaluated1/0,ln 0against the codomain; both were rebuilding this mechanism, and the thread on #1394 has the trail.)"x^x".Differentiate("x").Simplify(),"ln(x)/x"…,"x^n"…"ln(x) provided not x = 0".Simplify()ln(x)ln's domain condition overCCexcludes zero, the library's own statement thatln 0is a limit and not a value"tan(x) provided not cos(x) = 0".Simplify()tan(x)"sin(x)/x provided not x = 0".Simplify()sin(x)/x"1/(1 + x^2) provided not x = 0".Simplify(),"x/x provided not x = 0""(x + sin(x))/x".Limit("x", "+oo")11Recorded in the
Providedfsection ofSimplificationContract.md, the comparison page'sprovidedparagraph, and the #1396 entry of BREAKING-CHANGES (which now describes the mechanism rather than the list, with the two new rows). The wiki's Simplification page gains a section onprovidedwith four examples run on this build — committed on a local clone, pushed once this merges, since the wiki has no branches.Measured. All four test suites green (11,484). Performance gate PASSED: SimplifyEasy +0.9%, SimplifyHard +0.7%, allocation as the baseline says on all 19 gated rows — the domain condition is asked once per
providedanswer at theSimplifyboundary.Part of #1394.
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