Use the explicit linear constant-coefficient PDE operator and polynomial candidate coefficients=[-6, -1, 3, 3, -1, -1] in order [1,x,y,x²,x*y,y²]. Fix the operator convention before evaluating residuals. A point residual proves only a point check; general solution, existence, uniqueness and well-posedness remain separate obligations. principal [a,b,c]=[1, -1, 3] means a*u_xx+b*u_xy+c*u_yy, not 2*b*u_xy. source=-6, x=-1, y=3. Give (coefficients,principal,x,y,u_xx,u_xy,u_yy,source,signed residual,satisfied at the point?).
G001 — Use the explicit linear constant-coefficient PDE operator and polynomial candidate coefficients=[-6, -1, 3, 3, -1, -1] in order [1,x,y,x²,x*y,y²]. Fix the operator convention before evaluating residuals. A point residual proves only a point check; general solution, existence, uniqueness and well-posedness remain separate obligations. principal [a,b,c]=[1, -1, 3] means a*u_xx+b*u_xy+c*u_yy, not 2*b*u_xy. source=-6, x=-1, y=3. Give (coefficients,principal,x,y,u_xx,u_xy,u_yy,source,signed residual,satisfied at the point?).
Definition and scope
Use the original question domain, assumptions and cited MKO definitions. This item has second-context mathematical and bilingual review, with the model, answer and every arithmetic step independently recomputed from the original parameters; the source question remains a candidate.
u coefficients=[-6, -1, 3, 3, -1, -1];u_x=c1+2*c3*x+c4*y;u_y=c2+c4*x+2*c5*y
After
u_xx=6;u_xy=-1;u_yy=-2
Conditions: none
Differentiate each monomial by fixed-coordinate slice rules.The linear x term differentiates to a constant,and xy contributes c4 to u_xy.These are polynomial identities,not an assumed general mixed-partial exchange theorem.
The mixed term is b*u_xy,not the alternative convention2b*u_xy.Retain the query point roles even though these second derivatives are constant for this polynomial.
satisfied at declared point=No;no general solution claim
Conditions: none
This flag tests the residual at the declared point.A point pass does not generally prove a global solution or existence,uniqueness,regularity or well-posedness.A global identity requires a separate full symbolic residual audit.
The full substitutions and premise checks give the original answer; source identity,format and status are unchanged.
This question review and source binding
Review date: 2026-10-26
Original questions, answers, step expressions, numeric ASTs and historical records are retained. Source candidate labels remain historical and are not overwritten as formal proof.